English
tightlock
From tight + lock.
Today it means
noun A form of Janney coupler, typically used on North American mainline passenger rail cars, having mechanical features that reduce slack in normal operation and prevent telescoping in derailments, yet remain compatible with other Janney types.
Sources
Sources: Wiktionary, “tightlock”. By Wiktionary contributors, CC BY-SA 4.0, via kaikki.org (dump of Oct 3 2026); text adapted and restructured. Language periods are conventional ranges, not dates for this word. License.
Etymograph / tightlock