This is the 2992nd most frequent Russian word.
долей
"Долей" means "add" or "pour more" in the context of liquids.
In this sentence, 'долей' is used as an imperative form of the verb 'долить,' meaning 'to add more of a liquid.'
Пожалуйста, долей ещё воды в чайник.
Please add some more water to the kettle.
Here, 'долей' works as a command directing to serve more liquid, specifically tea, considering the social context.
Долей им чая за столом.
Pour them more tea at the table.
This usage of 'долей' emphasizes a practical instruction to adjust the consistency of a dish by adding liquid.