Cryptography is a term used where we keep information secure using some encoding mechanism and getting it decoded where it is supposed to be. For example, we transmit information from one place to another and want to keep it secure and safe from unauthorized access and getting it safely at receiving end, so some encryption are applied using a secret key before sending and get it decoded using the same key where it should reach safely.
In real scenario, generally it is used where any money transactional process happens there we don't want to take any risk. So, whenever one need to integrate an API for money transfer he is supposed to encrypt the information and send it to the endpoint and the same is applied when API provider returns back the resultant information.
Cryptography is also known cryptology.