Jiggs dinner means: A traditional Sunday evening meal eaten around Newfoundland and Labrador, typically consisting of salted beef boiled with vegetables.. It is mainly Canadian English and may not be understood outside that context. There is no real cause for parental concern; it is descriptive vocabulary rather than risky behaviour. If your teen uses it, context will usually make the intent clear. A short, curious question about where they heard it is usually all that is needed to know whether to follow up.