If you learn something by heart it means you know it or learn it perfectly.
To have something memorised perfectly.
- To know something so well that it has been thoroughly internalised.
1.The teacher told me to learn my speech by heart.
2. I love this song! I learnt all the lyrics by heart.
3. My grandmother learnt all the poems by heart.
4. The class learned the national anthem by heart in two days.
commit to memory, learn by rote, learn verbatim, learn word for word, memorise