Father

From Memory Alpha, the free Star Trek reference.

Father was the proper form of address for a priest of the Catholic denomination of Christianity on Earth. The character of Mulligan within the Fair Haven holographic program, played by The Doctor, was addressed this way. (VOY: "Fair Haven", "Spirit Folk")

Father is also the title of a male who has parented a child. Alexander often called Worf "father" (TNG: "Reunion"), et al.