"hashhouse" means: US colloquial term for a cheap, low-end diner or eating house — the kind of place that serves basic, unpretentious food at low prices. The w.... This is informal slang, common in casual speech, texting and social media, but not appropriate for school work, applications or professional settings. There is no real cause for concern in itself; it is everyday peer vocabulary. If your child uses it, a light comment about audience and register is usually enough — no need to escalate. Context, more than the word, tells you whether to follow up.