Learner's definition of JOY
1 [noncount] : a feeling of great happiness
Their sorrow turned to joy.
I can hardly express the joy I felt at seeing her again.
Seeing her again brought tears of joy to my eyes.
He found great joy in (doing) his work.
She answered the phone and, to her great joy, heard her son's voice on the line. [=she felt very happy when she heard her son's voice]
They were shouting/jumping for joy. [=they shouted/jumped because they were very happy]
— see also (little) bundle of joy at 1bundle
2 [count] : a source or cause of great happiness : something or someone that gives joy to someone
The flowers are a joy to behold!
What a joy it was to see her again.
the joy of sailing
the joys of parenthood
Her son is her pride and joy. [=her son makes her very proud and happy]
3 [noncount], British, informal : success in doing, finding, or getting something