This is the 3975th most frequent Turkish word.
damla
Drop.
The word 'damla' is used here to mean a 'drop' of liquid, indicating its literal context in the sentence.
Bir damla su her şeyi değiştirebilir.
A single drop of water can change everything.
The word 'damla' represents metaphorical droplets associated with the emotion of happiness in this context.
Gözlerinden mutluluk damlaları süzülüyordu.
Drops of happiness were streaming from her eyes.
Here, 'damla' is used in its plural form 'damlaları' to describe small droplets of rainwater literally.