Erect comes from the Latin word erectus, meaning  âupright, elevated, loftyâ or âeager, alert, aroused.â Erect is a verb, as in, it will take you years to erect your replica of the Eiffel Tower using only gum and toothpicks. Erect is also an adjective, as in something that is tall, firm, straight or rigid, like a half-dead plant that becomes more erect when you water it.
mathematical - characterized by the exactness or precision of mathematics; mathematical precision. math, mathematics, maths - a science (or group of related sciences) dealing with the logic of quantity and shape and arrangement.
In mathematics, an expression (or mathematical expression) is a finite combination of symbols that is well-formed according to rules that depend on the context.Mathematical symbols can designate numbers (constants), variables, operations, functions, punctuation, grouping, and other aspects of logical syntax.n general the meaning of expressions is not limited to designating values; for instance, an expression might designate a condition, or an equation that is to be solved, or it can be viewed as an object in its own right that can be manipulated according to certain rules.