Quendi
Original Elvish name for Elves (of every kind, including the Avari), meaning 'Those that speak with voices'.
>>>  Sundering of the Elves

Quenta Silmarillion   History of the Silmarils
The great collection of tales about the wars of the Eldar against Morgoth to regain the Silmarils.

Quenya
The ancient tongue, common to all Elves, in the form that it took in Valinor; brought to Middle-earth by the Noldorin exiles, but abandoned by them as a daily speech, especially after the edict of King Thingol against its use. Not named as such, but referred to as Eldarin or High Eldarin or High Speech.
>>>  Vanyarin, Noldorin, Telerin, Sindarin

Quickbeam
An Ent out of the Forest of Fangorn.