Is it ensure, insure, or assure?
early 14c., "line of descent, pedigree, descent," from Old French genealogie (12c.), from Late Latin genealogia "tracing of a family," from Greek genealogia, from genea "generation, descent" (see genus) + -logia (see -logy). An Old English word for it was folctalu, literally "folk tale." Meaning "study of family trees" is from 1768.
genealogy ge·ne·al·o·gy (jē'nē-ŏl'ə-jē, -āl'-, jěn'ē-)
A record or table of the descent of a person, family, or group from an ancestor or ancestors; a family tree.
The study or investigation of ancestry and family histories.