Lewis & Short

tesca (tesqua), ōrum (the sing. v. in foll.), n., rough or wild regions, wastes, deserts: tesqua sive tescua κατάκρημνοι καὶ ῤάχεις καὶ ἔρημοι τόποι, Gloss. Philox.: deserta et tesca loca, Att. ap. Varr. L. L. 7, § 11 Müll.; v. Varr. in loc.: loca aspera, saxea tesca tuor, Cic. poët. ap. Fest. pp. 356 and 357 Müll.; so, deserta et inhospita tesca, Hor. Ep. 1, 14, 19: nemorosa, Luc. 6, 41: remota, App. Flor. p. 358, 22; cf. id. ib. p. 348, 22. Such places were sacred to the gods: loca quaedam agrestia, quae alicujus dei sunt, dicuntur tesca, Varr. l. l.
Sing.: templum tescumque finito in sinistrum, an old religious formula, Varr. l. l.; cf. Fest. l. l.