Jesus nut

9.9

A strong metal part that holds a helicopter's rotor to its shaft and whose failure can cause a crash

noun
/ˈdʒiːzəs nʌt/

Jargon

: tuerca de Jesús

During maintenance, the engineer carefully inspected the Jesus nut for any signs of wear.

Examples

The pilot checked the Jesus nut before taking off to ensure everything was secure.
A loose Jesus nut can cause catastrophic failure in a helicopter's rotor system.
The helicopter's Jesus nut must be checked regularly.
If the Jesus nut fails, the helicopter could crash.
A loose Jesus nut can cause catastrophic failure in a helicopter's rotor system.
During maintenance, the engineer carefully inspected the Jesus nut for any signs of wear.
The pilot checked the Jesus nut before taking off to ensure everything was secure.

Surface Forms

Jesus nut singular

Jesus nuts plural

Morphology

Jesus + nut

The noun 'nut' clearly signals a mechanical fastener and 'Jesus' conveys a cultural/exclamatory sense of salvation or catastrophe, so a learner might infer this refers to an especially important or life-critical fastener. However, the exact technical meaning (the single rotor-retaining bolt whose failure causes catastrophic helicopter loss) is specialized, culturally marked and not predictable from the parts alone, so the phrase is only partially transparent to a B1 learner.

Etymology

Jesus nut comes from helicopter work, where one single big nut holds the main rotor in place. People said they would 'pray' to Jesus if that nut failed, so the name stuck, and today it means a single vital fastener whose failure would cause a crash.