Glossary beginning with H
The ability of organism to sense sound.
"An insect will be said to hear when it is demonstrably responsive to sound." 
"...the only distinction made between hearing and the tactile senses is based on the intensity factor and is quite arbitrary. Atthepresenttimenoconfusionarisesinpracticebecausethesensitivity of the auditory organs so far investigated is of a different order from the sensitivity of end-organs usually regarded as tactile. But the distinction is not fundamental, and it can be regarded as certain that further work will demonstrate the existence of end-organs intermediate in sensitivity between “hearing” and “tactile” end-organs. There will then be no justification for attempting a sharp separation." 
- The sound produced by a to- OR fro- movement of the stridulatory apparatus. Broughton (1963) took the view that this term should only apply to either of the components of a diplosyllable, preferring the term haplosyllable for syllables where either the to or fro motion was silent. Later authors (e.g. Ragge & Reynolds, 1998) often replace haplosyllable with hemisyllable.