noun
oil bottle; hair oil container
Historically a small bottle or pot for holding hair oil (椿油など). Now mostly encountered in historical or traditional contexts.
昔の日本女性は、油壺から椿油を手に取って髪に付けていた。
In the past, Japanese women would take camellia oil from an oil bottle and apply it to their hair.
noun
oilcup; oil cup
Mechanical part: a small reservoir that supplies lubricating oil to a bearing or moving part. Technical term.
この機械の軸受には、定期的に油壺から油を差す必要がある。
The bearings of this machine need to be oiled regularly from the oilcup.
noun
font; oil lamp font
The container part of an oil lamp that holds the oil. Also a technical or historical term.
古いランプの油壺に灯油を満たして火を灯した。
I filled the font of the old lamp with kerosene and lit it.
Compound of 油 (あぶら, oil) and 壺 (つぼ, pot/jar). The word transparently means 'oil pot'.