optical square
Surveying
noun
An instrument used to establish lines of sight at right angles to each other by using light bent through a right angle by mirrors or a prism.
Origin
Mid 19th century; earliest use found in William T. Brande (1788–1866), chemist.
- operating theatre
- operating voltage
- operation
- operational
- operational amplifier
- operational area
- operational expenditure
- operationalisable
- operationalisation
- operationalise
- operationalism
- operationalist
- operationality
- operationalizable
- operationalization
- operationalize
- operationally
- operational manager
- operational research
- operational researcher
- operation code
- operationist
- operation part
- operation room
- operations manager