ὕπαιθρος, ὑπαίθριος
(Phryn. Ecl. 221, Philemo [Vindob.] 396.17)

D. General commentary

Entries in the Atticist lexica of Phrynichus (A.1) and Philemon (A.2), echoed by Thomas Magister (B.4), recommend ὑπαίθριος rather than ὕπαιθρος as the correct form of the adjective meaning ‘in the open air’. Phrynichus’ explicit insistence on the correct number of syllables may suggest the enunciation of a rule concerning pronunciation, perhaps condemning a post-classical tendency to drop /i/ after a consonant and before another vowel (see Brown 2008, 226, who includes this phenomenon among cases of syncope). However, it is more likely that two morphological variants are contrasted (see entry ὀψαίτερος, ὀψίτερος for a partially similar case; in the latter case, however, it is more difficult to decide between a phonological and a morphological interpretation). The Synagoge adopts a different stance, depending on part of the tradition of Cyril’s lexicon (B.2), in which both forms are presented as semantically equivalent.

Both ὑπαίθριος and ὕπαιθρος are prepositional governing compounds of ὑπόὑπό ‘under’ and αἰθήραἰθήρ ‘sky, heaven, air’, resulting from the hypostasis of a phrase such as ὑπ’ αἰθέρι ‘under the (bright) sky’ (attested only in Hom. Il. 17.371 and Aesch. Eu. 368; the synonymous ὑπὸ αἴθρᾳ is attested much later, first in Paus. 10.10.6). Most such compounds have either *-o- or *-ii̯o- as a compositional suffix, while those without a suffix are rare (Sommer 1948, 107–9; Nussbaum 1986, 86–7). The form ὑπαίθριος, formed with the suffix -ιος, is first attested in Pindar (C.1) and predominates in Attic literary texts up to the end of the 5th century BCE, including tragedy (C.2, C.4), prose (C.5, C.6), and later comedy (C.10, C.11: see Orth 2020, 100 on the similarities between these passages as well as with the Platonic example in C.6). The rival form ὕπαιθρος, formed with the suffix -ος, is first attested in Hippocrates (C.7), albeit with the varia lectio ὑπαίθριος and besides two occurrences of ὑπαίθριος elsewhere in the Hippocratic corpus (Int. 21.32, Mul. 91.14), and it should be noted that other authors writing in non-Attic dialects, from Pindar to Herodotus (C.3), use ὑπαίθριος. In classical Attic prose, ὕπαιθρος is initially restricted to the adverbial expression ἐν (τῷ) ὑπαίθρῳ ‘in the open air’, first attested in Antiphon (C.8); in the adjectival sense, only ὑπαίθριος is used, as noted by LSJ s.vv. This distribution is well illustrated by a passage from Xenophon’s Oeconomicus (C.9), in which the concept of ‘outdoor works’ is rendered first as τὰς ἐν τῷ ὑπαίθρῳ ἐργασίας and then as ὑπαίθρια […] ἔργα. ὕπαιθρος becomes the more frequent form in the Hellenistic period, and its rise may be seen in the context of the loss of productivity of the inherited suffix -ιος < *-ii̯o- to create adjectives of appurtenance (see Sommer 1948, 151–2). According to Chantraine (1964, 11 n. 2), the later form ὕπαιθρος is a secondary modification of ὑπαίθριος and is distinct from the older substantivised neuter found in the phrase ἐν ὑπαίθρῳ. Adrados (1957, 112) argued, perhaps less convincingly, that ὑπαίθριος (in both the Attic and Ionic dialects) was derived from αἰθρία/-η ‘clear air’, while ὕπαιθρος was derived from Ion. αἴθρη: the presence of ἐν ὑπαίθρῳ in Attic prose, however, attests the former existence of αἴθρα in Attic.

In the koine, ὕπαιθρος came to acquire several specialised technicalTechnical language meanings. In Hellenistic military vocabulary, the term ὕπαιθροι designated ‘an army in the field, a military encampment, or detachment stationed outside a city in the countryside’ (Iossif, Lorber 2010, 435) as opposed to the κάτοικοι (‘military colonists’), while the neuter forms ὕπαιθρον or τὰ ὕπαιθρα designated a military camp (Chantraine 1964, 11); in discussions of military matters, the neuter plural τὰ ὕπαιθρα was also frequently employed to mean ‘the field’ or ‘open country’ as opposed to fortified places. These meanings are particularly frequent in historians such as Polybius, Diodorus Siculus, Dionysius of Halicarnassus, and Josephus (see Iossif, Lorber 2010, 435 nn. 10 and 11 for a selective list of passages). ὕπαιθρον also developed an architectural meaning referring to any open-air building or court (Hellmann 1992, 421) and was borrowed into Latin as the architectural term hypaethros (Vitr.+) ‘open to the sky, unroofed’, substantivised as hypaethron, -i ‘a temple open to the sky’ (see OLD s.v.); the Latin term was, in its turn, the basis for technical terms in modern European languages, such as French hypèthre or English hypaethral, attested since the 17th and 18th centuries respectively.

ὑπαίθριος, however, was never completely replaced, as it is still employed by prose writers through the Hellenistic and imperial ages, often side by side with ὕπαιθρος. Nonetheless, the later variant is clearly predominant: particularly telling examples are offered by Polybius, who overwhelmingly employs ὕπαιθρος (50x) against a single occurrence of ὑπαίθριος (16.12.3); Diodorus Siculus (with 27 occurrences of ὕπαιθρος against 6 of ὑπαίθριος); and Plutarch (with 23 occurrences of ὕπαιθρος against 3 of ὑπαίθριος). Closer examination reveals that the distribution is not random: while both variants are found in adjectival use, only ὕπαιθρος occurs in substantivised form (which, in fact, accounts for the majority of its attestations) and is consequently the only form admitted in the phrase ἐν ὑπαίθρῳ as well as in the technical military expressions outlined above, which together account for the vast majority of occurrences. The proportions change only slightly in more Atticising authors: Lucian uses the newer form (7x) more frequently than the older (4x), and the same may be said of Aelius Aristides (ὕπαιθρος 4x, ὑπαίθριος 2x); Philostratus, on the other hand, has only two instances of ὑπαίθριος (see Schmid, Atticismus vol. 4, 235). The criteria for the distribution are not dissimilar to those encountered in Hellenistic writers: Lucian, for instance, uses both forms in adjectival sense (and ὑπαίθριος, 4x, twice as often as ὕπαιθρος, 2x), but only ὕπαιθρος in the formula ἐν ὑπαίθρῳ (3x) and when substantivised (Symp. 20.12 ἐς τὸ ὕπαιθρον τῆς αὐλῆς ‘into the open court’).

Atticist lexicographers prescribed the older and longer form as the correct one. In addition to being better attested in canonical Attic literature, ὑπαίθριος might also be regarded as more morphologically regular, since it conforms to the same pattern as other adjectives from the same lexical family. In fact, in addition to the simplex αἴθριος ‘clear, bright’ (Hdt.+), several other – albeit rarer – compound adjectives in -αίθριος are known: ἐναίθριος ‘fully exposed’ (Thphr. CP 5.14.12); ἀλεξαίθριος ‘screening from chill air’ (Soph. fr. 117); and μιξαίθριος ‘characterised by an alternation of good and bad weather’ (Hp. Epid. 1.2.4). None of these, it should be noted, has a by-form in -αιθρος. A lone and late exception is δίαιθρος ‘fair, clear’ in Plu. Sull. 7.6 (but cf. διαιθριάζειν X. An. 4.4.10). From αἴθριος or from the noun αἰθρία ‘clear air’ is derived the denominal verb αἰθριάζωαἰθριάζω ‘expose to the air’ (Hp., Aesch., Arist.), which forms the basis for several prefixed compounds including, e.g., ἀπαιθριάζω, used by technical writers in the sense ‘expose to clean air’ but attested in Aristophanes (Av. 1512) as denoting ‘clear the clouds away’ (this Aristophanic usage attracted Phrynichus' interest in the Praeparatio sophistica: see B.1). The architectural term αἴθριον, attested from the 3rd c. BCE to designate an interior courtyard, is the substantivised neuter of the adjective αἴθριος rather than a folk-etymological adaptation of Latin ātrium (see Chantraine 1964; Dickey 2023, 31). Meanwhile, aside from the noun αἶθροςαἶθρος ‘clear, cold air of the morning’ (Hom. Od. 14.318), no simplex adjective *αἰθρος is attested of which ὕπαιθρος might have been considered a compound by ancient scholars; conversely, ὑπαίθριος could be seen as being supported in some way by the existence of αἴθριος. The late forms ἡ αἶθρος ‘courtyard’ (P.Lond. 3.1023.20 [TM 35717], Hermopolis, 5th–6th c. CE) and πρόαιθρον ‘vestibule of a courtyard’ (P.Flor. 56.1 [TM 23566], Hermopolites, 233–234 CE) are inverse derivatives of αἴθριον, according to Chantraine (1964, 11–2).

In focusing exclusively on the formal difference between the two variants, purist lexicographers overlooked their respective semantic nuances. Among erudite sources, only the synonymic lexicon attributed to Ptolemy of Ascalon (B.3) asserts a semantic difference between the two forms of the adjective, albeit in a somewhat puzzling way (see F.1). It is also surprising that the Atticist prescriptions fail to acknowledge that ὕπαιθρος is in no way foreign to classical Attic, since it is the only form admitted in the phrase ἐν ὑπαίθρῳ: one gets the impression that ὕπαιθρος was condemned wholesale owing to its dissemination in the koine. However, the Atticists were interested in the adjective's legitimacy, which a substantivised use – however widespread – could not guarantee. Meanwhile, it is less likely that the ὕπαιθρος proscribed by the Atticists was the outcome of a contemporary phonetic development in lesser-educated speech that coincidentally produced a form that was identical with the ὕπαιθρος attested since the classical period. On the loss of /j/ (arising from the synizesis of the unstressed prevocalic /i/) after /r/ in later Greek that might theoretically have produced such a form, see CGMEMG vol. 1, 20–2.

E. Byzantine and Modern Greek commentary

Both morphological variants survived into Post-classical Greek: both ὕπαιθρος and ὑπαίθριος are amply attested in Byzantine-era texts, although the former is more frequent. Modern Greek has on the one hand the adjective υπαίθριος -α -ο ‘outdoor’ and the substantivised feminine η ύπαιθρος, neuter το ύπαιθρο ‘countryside’ on the other (see LKN s.vv.).

F. Commentary on individual texts and occurrences

(1)    [Ptol.Ascal.] Diff.157 Palmieri (B.3)

This entry is taken from the so-called Ambrosian recension of the synonymic lexicon Περὶ διαφορᾶς λέξεων attributed to Ptolemy of Ascalon, transmitted in cod. A (= Ambrosianus E 26 sup. [15th–16th c. CE]) and probably compiled in the 11th or 12th century CE based on a 9th–10th-century source (see Palmieri 1982, 182). The entry, which is absent from other versions of the same lexicon, discusses an alleged difference in meaning between ὕπαιθρος and ὑπαίθριος: the former would properly refer to people who live in the open air, the latter to roofless buildings. As Palmieri (1982, 222) remarks, the semantic distinction between these words is unique to this lexicon (‘haec differentia auctori nostro deberi videtur’): other erudite sources either explicitly state that the two are equivalent (B.2) or prescribe one form over the other (A.1, A.2, B.4) but do not indicate any difference in usage (see Palmieri 1982, 222 for further parallel passages). Moreover, this alleged difference (perhaps influenced by ātrium?) is not clearly borne out by the two variants' textual distribution: as noted above (D.), it was in fact ὕπαιθρος that acquired specialised meaning in reference to buildings. The interpretation of the entry is rendered more difficult by the fact that the text of cod. A has ὕπαθρος and ὕπαιθρος (twice in this order) rather than ὕπαιθρος and ὑπαίθριος, which are Palmieri’s emendations.