For Advanced Level, the required notation is clearly set out in Appendix A of the Subject Content document.
You will also find further details on vocabulary and notation from all the examination boards.
OCR Specification A for example has very clear definitions and examples on instructions and words used in the specification. (Pages 11-13). From AQA we have Command Words.
WolframAlpha includes definitions, try a query on domain for example. WolframAlpha will assume that the query refers to a word, but note that you can refer to a mathematical definition.