ionic liquid 

Synonyms: ionic solvent, molten salt
https://doi.org/10.1351/goldbook.08180
Liquid that consists exclusively or almost exclusively of equivalent amounts of oppositely charged ions.
Notes:
  1. In practice, the ions are monocations and monoanions.
  2. Ionic liquids that are liquid at or around room temperature are called room-temperature ionic liquids (RTILs).
  3. The term ionic liquid has been often restricted to those water-free liquids that have melting points (or glass-transition temperatures) below 100 C, following a definition given by Walden, who prepared the first ionic liquid, ethylammonium nitrate, CHA3CHA2NHA3A+NOA3A, mp. 13 14C, for conductivity measurements.
  4. The terminology for ionic liquids is not yet settled, as stated by Welton. Room-temperature ionic liquid, non-aqueous ionic liquid, molten salt, liquid organic salt, and fused salt are often synonymous.
Source:
PAC, 2022, 94, 353. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)) on page 442 [Terms] [Paper]