Glossary of terms
A device in which data is represented by variable physical quantities that change continuously; not digital.
Angle of elevation:
The angle formed by the line of sight and the horizontal plane, for an object above the horizontal.
When referring to an inclinometer, the spectrum of angular readings that are provided.
The position of an aircraft or other craft determined by the relationship between its axes and a reference datum such as the horizon.
Refers to a type of analog inclinometer, which uses and indicator ball within a curved transparent tube, typically filled with damping fluid. Gravity acts upon the indicator ball to move it as the inclinometer tilts.
The angle of a long beam projecting from a telehandler, crane, derrick mast, etc., usually in relation to the horizontal plane.
The measure of the amount of rotation necessary to bring one line or plane into coincidence with or parallel to another line or plane.
A level indicator typically with curved tube assembly that contains no indicator ball, but instead a bubble in the damping fluid. Gravity moves the damping fluid to the lowest portions of the tube assembly, resulting in a bubble at the highest point of the curved tube.
Commonly used regarding Marine craft, this term is interchangeable with "inclinometer" (see below).
Liquid medium within an inclinometer tube assembly, designed to prevent excessive movement or oscillation of the indicator ball.
The degree of inclination of a road or slope, usually from the horizontal plane.
Inclination / Incline:
A deviation from true vertical or true horizontal. The angle determined by two lines or planes that are not parallel.
An instrument for indicating amount of incline, usually in respect to the horizontal plane.
A U.S. defense standard, often called a military standard, "MIL-STD", "MIL-SPEC", or informally "MilSpecs," is used to help achieve standardization objectives by the U.S. Department of Defense.
MIL-SPEC / MIL-STD:
Short for Original Equipment Manufacturer, an entity that produces complex equipment from components sourced internally and from other manufacturers.
Regarding marine craft and aircraft, to turn about a lateral axis so the forward end rises or falls in relation to the aft end. Compare to Yaw (below).
The extent to which an instrument yields the same results on repeated trials.
Reliability / Repeatability:
The fineness to which an instrument can be read. Resolution is not associated with reliability or accuracy.
To rotate from side to side about a front to rear axis, so the left side rises or falls in relation to the right side. With marine craft, often called "heel."
Steepness of a road or railroad. Commonly measured in angular degrees, percent slope, or grade to one (units of rise over horizontal units). Example: 20% slope means 1 unit of vertical distance or rise, for every 5 units of horizontal distance.
A device for establishing a horizontal line or plane by means of a bubble within a usually curved, liquid-filled transparent tube. Markings showing level condition (or zero degrees of tilt) and other angular measurements near zero are often displayed.
Spirit Level / Spirit Vial:
With aircraft, to turn by angular motion about the vertical axis of an airplane; sometimes unwanted left to right movement. With marine craft, to move from side to side or deviate erratically from a course.