個
ko
If it fits in your palm, it's 個
The picture A compact little lump that sits in your palm — not flat, not long, just a solid thing.
Where the picture shows up in 個
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a lump in the hand
たまごを六個ください。
tamago o rokko kudasai
Six eggs, please.
-
the price of one lump
この石けんは一個いくらですか。
kono sekken wa ikko ikura desu ka
How much is one bar of this soap?
-
a lump you swap in
トイレの電球が一個切れています。
toire no denkyū ga ikko kirete imasu
The bathroom light bulb has burned out.
-
the lump left over
おにぎりはあと一個だけ残っています。
onigiri wa ato ikko dake nokotte imasu
There's only one rice ball left.
-
a limit on lumps
お預けの荷物は一人二個までです。
oazuke no nimotsu wa hitori niko made desu
Two checked bags per person.
Flat things (paper, tickets) take 枚, long thin things take 本 — 個 is for the compact ones.