Ootheca \O`o*the"ca\, n.; pl. {Oothecae}. [NL., fr. Gr. w,'o`n an egg + ? a case.] (Zool.) An egg case, especially those of many kinds of mollusks, and of some insects, as the cockroach. Cf. {Ooecium}. [1913 Webster] Ooticoid