hold back within
"This soil retains water"
"I retain this drug for a long time"
"the dam retains the water"
allow to remain in a place or position or maintain a property or feature
"We cannot continue several servants any longer"
"She retains a lawyer"
"The family's fortune waned and they could not keep their household staff"
"Our grant has run out and we cannot keep you on"
"We kept the work going as long as we could"
"She retained her composure"
"this garment retains its shape even after many washings"
To keep in possession or use.
"The library retained its collection of rare books despite years of budget cuts."
In plain English: To keep something you already have so it doesn't get lost, stolen, or taken away by someone else.
"She was able to retain her seat on the bus during the sudden stop."
The word "retain" entered English from Anglo-Norman and later Middle French around the 14th century. Originally meaning to hold something back or keep it in possession, its core sense of maintaining ownership has remained largely unchanged since then.