The category of your topic (a "classification"), and one unique feature.
|TERM||is/are||CATEGORY||LINK||are more or less unique in some way|
|Crabs||are||large crustaceans||which||walk sideways|
|Dogs||are||domestic animals||that||were bred from wolves|
|"Dog"||refers to||domestic animals||which were||bred from wolves|
|Akita||is a kind of||Japanese Dog||,||made famous by Hachiko.|
|Happiness||is a form of||emotional state||caused by||eating chocolate|
|Happiness||can be defined as||an emotional state||which results from||eating chocolate|
|The word "dreich"||is a||Scottish term||which describes||cold, grey, dark, miserable weather.|
|Happiness||is defined here as||the emotional state which results from eating chocolate|
|Happiness||is here used to mean||a score of 5 or higher on the self-assessment Satisfaction scale|
|Happiness||is operationalised as||balance between positive and negative emotion (Ryff, 1989)|
Look at the first sentence of any Wikipedia article - it is a definition.
|Gold||is a||chemical element||with||symbol Au and atomic number 79.|
|Paper||is a||thin material||produced by||pressing together moist fibres of cellulose pulp|
|Economics||is the||social science||that||describes the factors that determine the production, distribution and consumption of goods and services.|
1) "Define" does not mean "copy a definition from a dictionary". Do you own research if you have to, and write your OWN definition.
2) Don't define in a boring way. We know what gold is. We know what paper is. Your unique detail must be something we don't know.