Formal:
* Multiply: This is the most common and general term for multiplication.
* Times: Often used in place of "multiply" in simple expressions, like "5 times 3".
* Product: Refers to the result of multiplication.
* Factor: Each number involved in multiplication is a factor.
Informal:
* By: "Multiply 3 by 5" is the same as "3 times 5".
* Of: "Half of 10" can be interpreted as 0.5 multiplied by 10.
* Double: Means to multiply by 2.
* Triple: Means to multiply by 3.
* Quadruple: Means to multiply by 4.
Other:
* Scale: Used when multiplying to enlarge or shrink something.
* Amplify: Means to multiply something, often used in relation to sound.
* Enhance: Means to improve something, often involving multiplication.
The best word to use depends on the specific situation and the desired level of formality.