As with many disciplines, the language of mathematics contributes both to its power and to the difficulty some students find in studying it. Access to a good technical dictionary can help, although all too often definitions are couched in the same arcane language which drove one to seek help in the first place. There are important distinctions to be made between the needs, say, of a typical 11-year-old, a primary school teacher and an undergraduate mathematician. All too often, existing mathematical dictionaries, of which there are many, have sacrificed usefulness by trying to serve too wide an audience.

The new Collins Educational School Mathematics Dictionary has been designed specifically for secondary school pupils aged 11 to 16. Its attractive design with spacious layout and large typefaces will improve its appeal to young people. With about 900 entries, it is less comprehensive than many of its competitors, but it represents a pretty thorough coverage of the main terms which will be encountered by pupils in key stages 3 and 4. It is very business-like with relatively concise definitions supported by examples and simple diagrams. There is occasional help on pronunciation and the derivations of some words are given.

The entries include a number of brief biographies of famous mathematicians, although the criteria for selection are by no means clear (R A Fisher is there, Alan Turing is not). References to units of measurement are staunchly metric - there are no signs of miles, pints or acres. The influence of recent developments in school mathematics is only partial. Pentomino and hexomino are defined but the more general polyomino is not, perfect numbers are explained but happy and sad numbers are not recognised. Some computing terms get in, including byte, LOGO and program.

A dictionary of this sort inevitably sacrifices completeness to provide accessibility. However, the assertion under tessellation that “octagons cannot tessellate the plane” is inexcusable. Many can.

Overall, this is a dictionary which meets its brief well and deserves a place in all secondary mathematics classrooms where, I predict, it will prove as useful to teachers as to students.