Aboideau means: A tide gate, designed to protect marshland, so constructed as to let out water at low tide, but to prevent an influx of water at high tide.. 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.