The Luer taper is a standardized system of small-scale fluid fittings used for making leak-free connections between a male-taper fitting and its mating female part on medical and laboratory instruments, including hypodermic syringe tips and needles or stopcocks and needles. Named after the 19th-century German medical instrument maker Hermann Wülfing Luer, it originated as a 6% taper fitting for glass bottle stoppers. Key features of Luer taper connectors are defined in the ISO 594 standards. It is also defined in the DIN and EN standard 1707:1996 and 20594-1:1993.
There are two varieties of Luer taper connections: locking and slipping. Their trade names are confusingly similar to the nonproprietary names. "Luer-Lok" and "Luer-Slip" are registered trademarks of Becton Dickinson. "Luer-Lok" style connectors are often generically referred to as "Luer lock", and "Luer-Slip" style connectors may be generically referred to as "slip tip". Luer lock fittings are securely joined by means of a tabbed hub on the female fitting which screws into threads in a sleeve on the male fitting. The Luer lock fitting was developed in the United States by Fairleigh S. Dickinson.
Slip tip (Luer-Slip) fittings simply conform to Luer taper dimensions and are pressed together and held by friction (they have no threads). Luer components are manufactured either from metal or plastic and are available from many companies worldwide.
- ISO 594:1986 "Conical fittings with a 6 % (Luer) taper for syringes, needles and certain other medical equipment". 
- DIN and EN standard 1707:1996 "Conical fittings with a 6 % (Luer) taper for syringes, needles and certain other medical equipment - Lock fittings".
- DIN and EN 20594-1:1993 "Conical fittings with a 6 % (Luer) taper for syringes, needles and certain other medical equipment described".
- Ravin A. (1952) A Luer slip with a rotating lock. J. Lab Clin. Med. 39(1), S. 168 PMID 14889106.