An HTLC is a contract making use of both a hashlock and a timelock. I noticed a discrepancy in what various sources state the abbreviation HTLC is short for. I've found:

What makes the most sense to be the canonical term? Please add supporting evidence.

  • I hate to say it, but given that you've yourself shown evidence of multiple distinct abbreviations being used in fairly high-profile contexts, I think there is no objective answer to that it stands for, and this is an opinion-based question... Aug 25, 2021 at 3:47
  • I'm hoping for some bitcoin-inclined linguists to provide their expertise on this matter. :)
    – Murch
    Feb 4, 2022 at 19:45

2 Answers 2


Using "hashed" makes it sound like the contract itself is hashed. Because the contract uses a hash, but is not itself hashed, I would say the H should stand for "hash".

Secondly, because "locked" applies to both the hash and the time components, I'd say it should be a separate word, rather than "timelocked".

Technically, initialisms can omit minor words like conjunctions (there is no standard either way, to the best of my knowledge), so while I haven't seen it used, a sensible meaning could be "Hash and Time Locked Contract." That's my two cents.


"Hash Time Locked Contract" according to the corresponding Bitcoin Optech topic page

I think term used by Bitcoin Optech is correct.

Please add supporting evidence

===Hash Time-Locked Contracts===

Hashed Timelock Contracts (HTLCs) can be used to create chains of payments which
is required for lightning network payment channels. The scheme requires both


  • 1
    Hah, that's funny. The quoted passage is titled "Hash Time-Locked Contracts", and then the first sentence defines "Hashed Timelock Contracts (HTLCs)".
    – Murch
    Aug 24, 2021 at 20:37
  • 1
    Right. I missed it. Confused and not sure which one is correct.
    – user103136
    Aug 24, 2021 at 20:41

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