出典:Wiktionary
出典:『Wiktionary』 (2025/07/21 04:22 UTC 版)
roller bearing (plural roller bearings)
By an arbitrary but widely upheld idiomatic convention, precise usage in mechanical industries often holds roller bearing and ball bearing to be coordinate terms under the hypernym of rolling-element bearing, in which case rollers that are spherical are excluded as referents of the word roller and are instead called balls.
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