(20) Intrā.
Intra is an Abl. Sg. Fem. of the same formation as inter, while intro is an Abl. Sg. Neut. (cf. ultrā and ultrō), and intus has the Adverbial ending -tos (ch. vii. § 1). Intus wavers between an Adverb and a Preposition in such a phrase as Virgil's tali intus templo, "in such temple within," or "within such temple."
(21) Juxtā.
Juxta, first used as a Preposition by Caesar, is Abl. Sg. Fem. of a stem juxto-, connected with jungo and meaning "adjoining."
(22) Ob.
Ob, I.-Eur. op(i) (Gk. ὄπι-σθεν), apparently a variety (ch. x. § 12) of epi (Gk. ἐπί), often retains its -p in Latin spelling in Compounds like op-tineo, op-erio (see ch. ii. § 10). In classical Latin it has the sense of "before" (e.g. ob oculos ponere, to describe), or "on account of," but in the earlier literature also of "around," "to," "near," &c.
(23) Pǎlam.
Palam, like its opposite, clam, an Acc. Sg. Fem. of some stem connected with palari, to wander, be dispersed abroad. It is not found as a Preposition till the Augustan Age.
(24) Pěněs.
Penes (governing the Acc., usually of a person) is a suffixless Locative (ch. iii. § 8) of penus, -oris, from the root pen- of penitus, pene-tro.
(25) Per.
Per, through, connected with I.-Eur. perō, "I transport, bring or pass through" (cf. Gk. πείρω, Lat. ex-perior), corresponds to Gk. περί in its intensive sense (e.g. per-longus, Gk. περι-μήκης); to Gk. παρά in its sense of wrong or injury (e.g. per-jurus, per-do, per-fidus; Gk. παρ-όμνυμι, παρα-βαίνω), these two Gk. Prepositions being really different cases of the same root per-, as are also Lat. pr-ō, pr-ae.
(26) Post.
Post, O. Lat. postē, for pos-ti, often became in Compounds through loss of t (ch. x. § 20) pos; e.g. posquam was according to some Grammarians the proper spelling in Virg. Aen. iii. 1; po-merium for pos(t)-moerium. With addition of the suffix -ne (§ 1) it becomes pone.
(27) Prae.
Prae, before, is a Dative formation from the root per- (see above). Prae-sens has the old sense of "being in command" (cf. prae-fectus, prae-positus) in the inscription on the Columna Rostrata, praesented dictatored olorum "praesente dictatore illorum."
(28) Praeter.
Praeter, past, except, is formed from the preceding by means of the suffix -tero- like the Adverbs breviter, &c. (ch. vii. § 2).
(29) Pro.
Pro is I.-Eur. prō (Gk. πρό, πρω-ί, early). It retains in class. Lat. the short vowel before f, e.g. prŏ-ficiscor, prŏ-fundo (but prō-ficio); but in the early literature prŏ- is much more frequent than it is in the classical period; the Adj. prŏ-bus (cf. super-bus, Gk. ὑπερ-φυής) preserves this form. In prodest, prodire, pro is augmented by the particle -de (§ 1).