Definition of LIFETIME TRUSTEE:
(noun) / a trustee acting under a lifetime trust (SCPA § 103 [32])
Plain English Translation: There are trusts made by a person during life (aka living trusts) and there are trusts created within a last will and testament that only go into effect after the creator dies and once the will is admitted to probate (testamentary trusts). The trustee of a lifetime trust is referred to as a lifetime trustee (vs a testamentary trustee).