Lewis & Short

sŭb-ālāris, e, adj., that is under the arms, placed or carried under the arms: telum, Nep. Alcib. 10, 5: culcitae, Lampr. Heliog. 19 fin.
As substt.

    1. 1. sŭbālāres, ĭum, f. plur., the feathers under the wing, Vulg. 4 Esd. 11, 25.
    2. 2. sŭbālāre, is, n., an under-girdle, Edict. Diocl. p. 25; cf. Isid. Orig. 19, 33.