A regent is the person who runs a country for a king or queen who cannot do the job themselves. The usual reasons are that the ruler is still a child, is very ill, or is away for a long time. The crown still belongs to the king or queen; the regent is only holding the steering wheel until they can take it back, so the job is meant to be temporary.

for a king or queen who cannot do the job themselves替沒辦法親自執政的國王或女王, a regent is regent 就是 the person who runs a country代為治理國家的人。The usual reasons are通常的原因是: the ruler is still a child統治者還是小孩, is very ill病得很重, or is away for a long time或者出遠門很久。The crown still belongs to the king or queen王位仍然屬於國王或女王; the regent is only holding the steering wheelregent 只是暫時握著方向盤 until they can take it back等他們能拿回來為止, so the job is meant to be temporary所以這個職位本來就是暫時性的。

History books talk about a prince regent or a queen regent when that person is acting in this stand-in role.

History books歷史書 talk about會提到 a prince regenta prince regent（攝政王子） or a queen regent或 queen regent（攝政女王） when that person is acting in this stand-in role指的就是扮演這種代理角色的人。

Though actually, in the United States you will also see Board of Regents — a group that governs a university, not a royal stand-in. Same old idea of “people who govern,” different setting.

Though actually不過其實, in the United States在美國 you will also see你還會看到 Board of RegentsBoard of Regents（校董會） — a group that governs a university是管理大學的一個團體, not a royal stand-in不是王室代理人。Same old idea of "people who govern,"一樣是「治理者」這個老概念, different setting只是換了個場景。

The word feels formal and a bit historical; you would not call a babysitter a regent unless you were joking in a fancy way.

The word feels formal and a bit historical這個字感覺正式又帶點歷史感; you would not call a babysitter a regent你不會把保母叫做 regent unless you were joking in a fancy way除非你是在開一個很誇張的玩笑。