Daleside means: A British geographical descriptor for the side or slope of a dale - a valley, particularly in northern England where 'dale' is the standard word for a river valley . Used as a noun or in. 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.