Origin of the name

The most usually given source is Glott’s Hop or Glott’s valley - Glott being the personal name of someone who held, or farmed, land hereabouts. This seems to be consistent with ‘-hop’ or ‘-hope’ meaning a side valley or branch off the main one, but the word Glott as a personal name is apparently not recorded elsewhere.
It has been thought that Glott could mean ‘starer’ [as in ‘gloat’] and it would seem that Mike Harding the folk singer thinks it is to do with the number of celtic-style carved staring stone heads which once could be found in this area.
There are categories of name that come from a combination of two old languages. Where Anglo-Norse names are concerned they are known as ‘Grimston hybrids’ and where they derive from Anglo-Saxon-Celtic languages they are known as ‘Bredon hybrids’.
The scholars offer an all-Anglo-Saxon "Side-valley of the Starer" or a Bredon-type hybrid - "Side-valley of the stream called "Glwys" or "Glws" meaning "Grey" or "Silver".
It is reasonable - especially if the River Etherow (which Glossop Brook joins near the Roman fort at Melandra) had a Welsh name, such as "Teign" meaning "Roarer" (presumably there were rapids where Tintwistle now is, before the Longdendale reservoirs were built). "Etherow" is presumably a Celtic or pre-Celtic name. It crops up often enough in Spain/Portugal.

The name Glossop is thought to be of Saxon origin, derived from Glott's Hop - where hop is a small valley and Glott was probably a chieftain's name. However, the area was certainly inhabited long before the Saxons, as the Bronze Age burial site on Shire Hill and the Bronze Age remains around Torside testify. When the Romans arrived in 78 AD the area was under the control of the Brigantes, a tribe whose main base was in Yorkshire, and the main purpose of the fort at Melandra was to subjugate this warlike tribe