| 158454 | Muyu, North | ok | | | McElhanon and Voorhoeve (1970) | water |
| 201400 | Mandobo Atas | ok | | | Voorhoeve (2000) | |
| 201482 | Mandobo Atas (Yonggom Dialect) | ok | | | Voorhoeve (2000) | |
| 229502 | Proto-Dumut | *ok | | | Healey (1970) | |
| 201815 | Proto-Dumut | *ok | | | Voorhoeve (2000) | |
| 31220 | Zimakani (South Boazi Dialect) | ɑɔḳ | | | Voorhoeve (1970) | |
| 30406 | Tamagario | okom | | | Voorhoeve (1971) | |
| 20541 | Tamagario | okom | | | Voorhoeve (1975) | |
| 209396 | Proto-Trans-New-Guinea | *ok(u) | | | Ross (2014) | water |
| 184757 | Proto-Trans-New-Guinea | *ok[V] | | | Pawley (2005) | |
| 243934 | Yessan-Mayo | okw | | | Laycock (1968) | |
| 243935 | Yessan-Mayo (Warasai Dialect) | okw | | | Laycock (1968) | |
| 243933 | Mehek | okwu | | | Laycock (1968) | |
| 124323 | Girawa | ɔ:m | | | Z'graggen (1980) | water |
| 143304 | Musar | ɔːmbɔ | | | Z'graggen (1980) | (water) |
| 158510 | Tuma-Irumu (Irumu Dialect) | ome | | | McElhanon and Voorhoeve (1970) | water |
| 158464 | Pare | omɛ | | | McElhanon and Voorhoeve (1970) | water |
| 158465 | Pare | ɔmɔɛ | | | McElhanon and Voorhoeve (1970) | water |
| 74757 | Gimi | one' | | | Scott (1978) | |
| 219774 | Awyu, Central (Nohon Dialect) | ˈoɣo | | | Kriens & Lebold (2010) | |
| 229774 | Aghu | oɣo | | | Healey (1970) | |
| 219526 | Awyu, Central (Ketah Dialect) | oɣo | | | Kriens & Lebold (2010) | |
| 220015 | Awyu, Central (Taim Dialect) | oˈɣo | | | Kriens & Lebold (2010) | |
| 17261 | Northeast Kiwai (Arigibi Dialect) | o'obó | | | Wurm (1973) | |
| 20784 | Faiwol (Kauwol Dialect) | ook | | | Voorhoeve (1975) | |
| 243937 | Iwam | op | | | Laycock (1968) | |
| 237610 | Iwam | o(p) | | | Foley (2005) | |
| 91226 | Kâte | opâ | water | | McElhanon (1967) | water |
| 143302 | Mawak | opɛt | | | Z'graggen (1980) | (water) |
| 143303 | Pamosu | opɛt | | | Z'graggen (1980) | (water) |
| 158545 | Kâte (Wemo Dialect) | opo | | | McElhanon and Voorhoeve (1970) | water |
| 143301 | Kowaki | opot | | | Z'graggen (1980) | (water) |
| 158543 | Kâte (Mâgobineng Dialect) | opu | | | McElhanon and Voorhoeve (1970) | water |
| 20744 | Ngalum | oq | | | Voorhoeve (1975) | |
| 25396 | Yongkom | oq | | | Voorhoeve (1975) | |
| 214257 | Wambon | ʔɔq | | | Hughes (2009) | |
| 207705 | Proto-Maria | *ʔoru | | | Ross (2014) | water |
| 258128 | Maria (Maiagolo Dialect) | ˈoru | | | Dutton (1970) | water |
| 258132 | Maria (Uderi Dialect) | ˈoru | | | Dutton (1970) | water |
| 258130 | Maria (Maranomu Dialect) | ˈʔoru | | | Dutton (1970) | water |
| 258129 | Doromu-Koki (Lofaika Dialect) | ˈʔoru | | | Dutton (1970) | water |
| 258134 | Maria | ˈʔoru | | | Dutton (1970) | water |
| 17973 | Edolo | ɔ̃tã | | | Shaw (1986) | |
| 28303 | Zia (Mawai Dialect) | ou | | | Wilson (1969) | |
| 91220 | Somba-Siawari (Mindik Dialect) | ou | water | | McElhanon (1967) | water |
| 91225 | Somba-Siawari (Burum Dialect) | ou | water | | McElhanon (1967) | water |
| 55706 | Binandere | ou | water | | Smallhorn (2011) | |
| 158551 | Zia (Mawai Dialect) | ou | | | McElhanon and Voorhoeve (1970) | water |
| 55695 | Suena | ou | water (river, fresh) | | Smallhorn (2011) | |
| 27878 | Zia | ou | | | Wilson (1969) | |
