defining

Everyday

1. Most important in showing what someone or something is really like: «a defining moment». tree →
2. (verb) Giving the exact meaning of a word, or setting out the limits of something. tree →
3. (grammar) A «defining relative clause» gives information that tells you exactly which person or thing is meant. tree →

In the lessons

In stories a «defining moment» is the event that changes a character for ever. In English lessons, «defining» clauses use «who», «which» or «that» without commas: «The girl who won the race is my sister.» In maths and science, «defining» a word gives its exact meaning, such as defining a prime number. Phrases: «a defining moment», «a defining feature», «defining characteristic».

Examples

• Winning the final was a defining moment for the team. tree →
• A defining feature of a triangle is that it has three sides. tree →
• We are defining the new words in our vocabulary books. tree →
• Kindness is her defining quality. tree →
• Defining what a «fair» game means helped end the argument. tree →
• In the sentence «The book that I read was long», «that I read» is a defining clause. tree →

Note

The verb is «define»; the noun is «definition». «Definitive» is a different word meaning final or best. Defining clauses take no commas; non-defining ones need commas.