This is the 2345th most frequent Turkish word.
eliyle
"With his/her hand" or "by hand."
The word "eliyle" is used to indicate the means by which an action is performed, emphasizing the woman's own hand being used to water flowers.
Kadın eliyle çiçeklere su verdi.
The woman watered the flowers with her hand.
Here, "eliyle" shows direct physical interaction while performing the action of adding salt during cooking.
Yemek yaparken eliyle tuzu ekledi.
While cooking, she added salt with her hand.
In this case, "eliyle" specifies a method of writing, indicating a handwritten letter as opposed to a typed one.