# Glossary O

object | See data object.
object file | The binary output of a language processor (such as an assembler or compiler), which can either be executed or used as input to the linker.
obsolescent feature | A feature of earlier versions of Fortran that is considered to be redundant in Fortran 2018. These features are still in frequent use.
octal constant | A constant that is a string of octal (base 8) digits (range of 0 to 7) enclosed by apostrophes or quotation marks and preceded by the letter O.
operand | The passive element in an expression on which an operation is performed. Every expression must have at least one operand. For example, in I .NE. J, I and J are operands. Contrast with operator.
operation | A computation involving one or two operands.
operator | The active element in an expression that performs an operation. An expression can have zero or more operators. Intrinsic operators are arithmetic (+, -, *, /, and **) or logical (.AND., .NOT., and so on). For example, in I .NE. J, .NE. is the operator. Executable programs can define operators which are not intrinsic.
optimization | The process of producing efficient object or executing code that takes advantage of the hardware architecture to produce more efficient execution.
optional argument | A dummy argument that has the OPTIONAL attribute (or is included in an OPTIONAL statement in the procedure definition). This kind of argument does not have to be associated with an actual argument when its procedure is invoked.
order of subscript progression | A characteristic of a multidimensional array in which the leftmost subscripts vary most rapidly. Also called column-major order.
overflow | An error condition occurring when an arithmetic operation yields a result that is larger than the maximum value in the range of a data type.

Parent topic: Glossary