‖ thecium Bot.
(ˈθiːsɪəm)
[mod.L., a. Gr. θηκίον, dim. of θήκη theca.]
The hymenium of a lichen.
| 1882 J. M. Crombie in Encycl. Brit. XIV. 554/1 The two principal parts of which an apothecium consists are the hypothecium and the thecium. Ibid. 554/2 The thecium, or as it is more frequently termed the hymenium, is that part of the apothecium which contains the organs of the fruit. |