An Etymological Dictionary of Astronomy and Astrophysics

1. Adequate for the purpose; enough.
   

2. Logic, Math.: A condition which, if true, guarantees that a result is also true. However, the result may also be true if the condition is not met.
   → if and only if.

Etymology (EN): M.E., from O.Fr. sufficient, from L. sufficiens, pr.p. of sufficere “supply, suffice,” from sub “up to,” → sub-, + root of facere “to make,” → fact.

Etymology (PE): Basandé “sufficient, complete, worthy,” from *basidan, from bas “many, much,” → multi-.