base-dependent digit: the maximum possible single-digit number expressible in the relevant number base.
Some pathologies are possible. For a non-balanced, fixed, positive, arithmetic base (such as standard binary, decimal, hexadecimal), this is one less than the base (respectively: '1', '9', 'F'); in such a case, this word is equivalent to "vei (vei) pano (ju'u ny ve'o) vu'u pa ve'o boi'ai".