Single-entry bookkeeping, also known as, single-entry accounting, is a method of bookkeeping that relies on a one-sided accounting entry to maintain financial information.
Double entry accounting often requires commitment which most sole proprietors cannot afford to do or simply are not interested in.
As such, the practice of keeping partial records of business related transactions which is outside the requirements of double entry book keeping is called “single entry accounting” / “Accounting for incomplete records”.
[1] Most businesses maintain a record of transactions using double-entry bookkeeping.
However, many smaller businesses use single-entry books that record the "bare essentials."