補遺 is read as ほい (hoi) and means supplement.
ほい
hoi
ゆいごんほそくしょ
codicil
いぞくほしょう
compensation to the bereaved family
ほさ
aid
ほしょう
compensation
ほじゅう
replenishment
ほしゅう
repair
ほちょうき
hearing aid
ほてん
covering (a loss, deficit, etc.)
ほてんきん
compensation money
ほさにん
assistant
ほさてき
supportive (role)
ほきゅうきち
supply base