Finally, let’s revise by looking at some odd examples of acronyms and initialisms, then I’ll present some exercises.
The light-emitting diode is commonly abbreviated as ‘LED’, from the initial letters of each word, ‘l’, ‘e’, and ‘d’. This would very easily make an acronym (a set of initials that can be read or said as a word) pronounced as ‘led’ (to rhyme with ‘bed’). However, it is almost universally said as an initialism (a set of initials read or said as the individual letters), as ‘L, E, D’ (‘ell, ee, dee’).
In physics, chemistry, and statistics, it is common to refer to the number of degrees of freedom (DOF, also d.o.f. and D.o.F.), that is, the number of parameters of a system that may be adjusted or the number of directions a body may move in. Here, DOF is an initialism, pronounced as the letters ‘D, O, F’. We can define one degree of freedom (1DOF) or a single degree of freedom (SDOF), two degrees of freedom (2DOF), three DOFs (3DOF), and then speak of a body having a SDOF, that it has 1DOF or 2DOFs, or refer to a whole 3DOF-system (a three-degree-of-freedom system).
Lidar, a surveying technique that uses laser light to measure distances to objects and map an environment, was originally named as a portmanteau of “light” and “radar”, that is, ‘li-’ and ‘-dar’. In concept, like radar (for RAdio Detection And Ranging), it may be thought of as ‘light detection and ranging’. However, as a result, many writers assume that it is an acronym and call it LIDAR (for LIght Detection And Ranging). All kinds of capitalizations are now in use: lidar, Lidar, and LIDAR are the most common, but LiDAR and even LIDaR can be found.