organism – an individual living thing

To remember the meaning of organism, use the following mnemonic:

The organ attracted a lot of tourism (organism) and many individuals stood in my living room to see it. 

An organism is a living thing made up of one or more cells and can carry out all the life processes (MRS GREN).

Living organisms are separated into what's known as the five kingdoms, grouping them based on fundamental characteristics such as how they feed, reproduce and what their cell structure is. The five kingdoms are as follows; animals, plants, fungi, protists and bacteria. (LINK to remember to five kingdoms).