The word 'lap' can mean the top part of your legs when you sit down. It can also mean to drink something by moving your tongue, like how a dog drinks water.
You say 'lap' like this: it rhymes with 'map' and 'cap'. It sounds like 'l' followed by 'ap'.
The word 'lap' comes from an old English word that means to fold or to lay something over. It has been used for a long time!