adumbral, a.
(əˈdʌmbrəl)
[f. L. ad to + umbra shade + -al1; with reference to adumbrāre, adumbrate v. 4.]
1. Of overshadowing nature; shady.
| 1845 Blackw. Mag. LVII. 246 This circular adumbral and pluvial roofing had to be adapted to the female head. |
2. Zool. A shortened equivalent of adumbrellar.
| 1881 E. R. Lankester in Jrnl. Microsc. Sc. Jan. 124 The cells of the adumbral walls are like those of the ring-canals. |