Lefthandside

Lefthandside, more commonly written as left-hand side, is a conventional term used to designate the portion of an expression that appears to the left of an equals sign or other relational operator. The left-hand side is typically abbreviated LHS, with the right-hand side abbreviated RHS. The concept is used across mathematics, logic, and related disciplines to distinguish the two sides of an equation, inequality, or assignment.

In mathematics, the LHS is the expression that is set equal to or related to the RHS. For example, in the equation 3x + 2 = 7, 3x + 2 is the LHS and 7 is the RHS. In inequalities such as f(x) ≤ g(x), the LHS consists of the expressions on the left of the relation symbol. The LHS and RHS terminology helps structure and manipulate equations, especially when solving for variables or proving identities.

In programming and logic, the term can have additional nuance. In assignments, the left-hand side refers to the target that receives a value, commonly known as the lvalue in many languages. In logical expressions, the LHS is the part of the statement being asserted before the relation or operator.

In everyday language and interface design, left-hand side sections of a layout often contain navigation or controls, reflecting a spatial convention rather than a formal mathematical concept.

Note that lefthandside as a single word is not standard; the preferred spelling is left-hand side, or the abbreviation LHS when used in technical writing.