This is the 6417th most frequent Japanese word.
ジョーク
"ジョーク" means "joke" in English.
In this context, 'ジョーク' is used to describe a specific humorous statement intended to entertain or lift spirits.
ジョークを言って場を盛り上げました。
He told a joke to lighten up the atmosphere.
Here, although 'ジョーク' is not directly used (冗談 is the Japanese equivalent), it conveys the idea of humor or jest in a situation being contrasted with seriousness or earnestness.
冗談ではない、本気で言っているんだ。
This is not a joke; I am serious.
Here, 'ジョーク' refers to verbal jokes or humorous remarks exchanged in conversation.