Grice uses Latinate "rational" AND Grecian "logical"

rătĭōnālis , e, adj. ratio.

I. Of or belonging to accounts (post-Aug.): LITTERAE, Inscr. (a. p. Chr. 193) Orell. 39.—Hence, subst.

(α). rătĭōnālis , is, m., an accountant, receiver of revenue, treasurer, Lampr. Alex. Sev. 45; 46; Capitol. Gord. 7; Commod. ap. Capitol. Albin. 2; Amm. 15, 3, 4; Inscr. Orell. 1090.—

(β). rătĭōnāle , is, n., the oracular breastplate of the Jewish highpriest, Vulg. Exod. 25, 7; id. Lev. 8, 8; also called rationale judicii (transl. of LXX. τὸ λογεῖον τῆς κρίσεως), id. Exod. 28, 15.—

II. Of or belonging to reason, reasonable, rational, endowed with reason: “falsa est (finitio), si dicas, Equus est animal rationale: nam est equus animal, sed irrationale,” Quint. 7, 3, 24: “homo est animal rationale,” id. 5, 10, 56; cf. id. 5, 8, 7; and: “nec si mutis finis voluptas, rationalibus quoque: quin immo ex contrario, quia mutis, ideo non rationalibus,” id. 5, 11, 35; so without a subst.: “a rationali ad rationale (translatio),” id. 8, 6, 13.—

B. Reasonable, depending on reason: “in causā rationali,” Auct. Her. 2, 12, 18: “philosophia,” i. e. logic, Sen. Ep. 89, 17; “also called rationalis pars philosophiae,” Quint. 12, 2, 10: disciplina, i. e. theoretical science (opp. to usus and experimenta), Cels. praef.; “also ars,” id. ib.; hence, rationalis medicina, theoretical therapeutics; “and rationales medici,” medical theorists, id. ib.—

2. In rhet., i. q. ratiocinativus, of or belonging to a syllogism, syllogistic: “genus (quaestionum),” Quint. 3, 5, 4; 6, 54; 78; 86; cf. “status,” id. 3, 6, 56; 66.— Hence, adv.: rătĭōnālĭter , in a reasonable manner, reasonably, rationally, Sen. Ep. 109; Tert. Anim. 16 al.