at one's beck and call

"at a person's beck and call"という慣用表現があります。

"beck"というのは"beckon"（合図する、差招く）という動詞を短縮したものです。

"call"は「呼ぶ」です。

従って、"at one's beck and call"というのは、他人の指図や呼び声の言いなりである、という意味です。

"beck"も"call"も、同じような意味の単語を並べていることでは冗語表現の一種と言えるかと思います。

Dear Mum and Dad,

It's your dog Clancy, writing from the city. Quick question: when did I leave the home of my birth? My memory: when I was ten weeks old. Have I prospered since then? I think I have. Have I troubled you in any way, requesting your assistance? The answer, I believe, is in the negative.

What a contrast with the world of humans. Man and Lady have two sons, nice young chaps. Both lived at home through their teenage years. By then they were able to eat solid food and keep themselves clean, yet despite these achievements, they were still living with their parents – aged fifteen, sixteen and even seventeen – like dependent puppies. Why?

Even now they've left, Man and Lady are at their beck and call. As soon as one of them makes contact, it's like the situation room at the White House. Incoming! All hands on deck! Quick – the offspring need us!

(Richard Glover. Why are parents at the beck and call of their adult kids? Sydney Morning Herald. October 2, 2020.)

引用したのは、イヌの視点から見た人間の子供（いい大人？）という、面白い文章です。