バイクbaiku

1. nounmotorcycle; motorbike; bike
   ビルはバイクをとても欲ほしがった。↗

   Bill was crazy for a motorbike.
2. nounbicycleusu. in compounds

• SynonymモーターサイクルNeutralFull loanword for a motorcycle, mostly seen in brand and show names; rare in everyday use — say 「バイク」 instead.
• SynonymオートバイNeutralA standard word for a motorcycle, also used in current legal definitions; 「バイク」 is more common and can also mean a bicycle.
• Synonym自動二輪車じどうにりんしゃFormalFormal legal term for a motorcycle above a set engine displacement, seen in driving licences and traffic laws; in everyday speech people say 「バイク」.
• Synonym単車たんしゃCasualColloquial name for a motorcycle with an old-fashioned or enthusiast flavour; 「バイク」 is the usual everyday word.
• SynonymモーターバイクNeutralLoanword for a motorcycle with few examples in actual use; 「バイク」 or 「オートバイ」 is the usual choice.

Everyday speech defaults to 「バイク」, which can also mean a bicycle; 「オートバイ」 is also in common use. Use 「自動二輪車」 in legal contexts and 「単車」 for a colloquial, old-school flavour; the other loanwords are rare.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 原動機付自転車げんどうきつけじてんしゃ。自動じどう二輪車にりんしゃ。
2. 自転車じてんしゃ。