1911 Encyclopædia Britannica/Obit

OBIT (through O. Fr., from Lat. obitus, death, obire, to go down, to die), a term for death, formerly used for the account of a person’s death (now “obituary”). An “obit” was also a service performed at a funeral or in commemoration of a dead person, particularly the founder or benefactor of a church, college or other institution, hence “obit-days,” “obit Sunday,” &c. A “post-obit” is a bond given as a security for the repayment of money lent upon the death of a person from whom the borrower has expectations (see Bond).