As a Noun: 1. In mathematics, the calculation of the total of two or more numbers. English = addition. 2. In mathematics, the addition or plus symbol (+) which is put between two numbers to show that they are to be added together. As a Verb or Adjective: 1. In mathematics, to calculate the total of two or more numbers. English = add. 2. To put two things in the same place, to say one more thing. English = add. 3. In mathematics, to be a number which is greater than zero. English = (be) positive. 4. In mathematics, the sign for the word used to name the operation of adding two numbers together and represented by the symbol +. English = plus. As Modifier: 1. Used to link two or more words, groups, or clauses. English = and.