Can the term encryption refer to simple security actions?

Question

Security actions such as: putting a lock on a diary to stop people from reading what is written inside, or putting a password on a file.

Answer 1

No, I would call those things "security" instead of encryption. Encryption means to make file unreadable by scrambling the information in such a way that it can only be read using a hardware or software key. Some encryption is very simple and some is complex, but all work by replacing clear data with scrambled and unreadable data.