Roots/*h₁en-dʰoh₁en-dʰo“into, within”Widely accepteddirectionspatialendo-, endogenousExtended form of *h₁en yielding Greek endo-, English endogenous, endocrine.Related Rootsdeyḱ-eyo-“to keep pointing, indicating”dʰewb-mn̥“depth, deep place”dʰewb-₂“to be deep, hollow”gʷeyd-eyo-“to keep seeing, watching over”gʷeyd-mn̥-“a knowing, recognized thing”h₁en-tero-“inner, interior”h₁epi“upon, at, near”h₁epi-₂“upon, over, afterwards”