1. 河口：osteocolla 多孔石灰华 | ostiary 河口 | ostracoda 介形类

2. 看门人：osteotomy 切骨术 | ostiary 看门人 | ostiole 小孔

noun

1. someone who guards an entrance

    Synonym: doorkeeperdoormandoor guardhall porterportergatekeeper

2. the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church

    Synonym: doorkeeperostiarius