Hi bhuwan,

it's very simple concept which applicable for any programming language or data related operation.

the record means any single record (single row of data) and recordset means number of records ( multiple row of data) it's like data row in database table.

in the term of odoo, like a create method return single record and when you search something in model/table then it may return multiple records/recordset.

for more reference read this

https://odoo-new-api-guide-line.readthedocs.io/en/latest/environment.html

dont forget to accept and upvote answer if helpful.

thank you.