The Etymology of Bath
Bath is older than the language itself and tells a quietly different story from cleanliness. The Proto-Indo-European root *bhē- (to warm) is the source — not a root meaning to wash, but to heat. The Germanic *baþą named a session of steam, hot water, and warmth, where cleaning was a side effect of the heat. Roman Britain inherited a sophisticated bathing culture, and the Saxons who arrived after Rome's collapse renamed the great Roman thermae complex in Somerset simply Bath, after their own warm-water tradition (the Romans had called it Aquae Sulis, the waters of Sulis, after the local Celtic goddess). The same Germanic root gives us bask (originally to bathe in heat), Bath itself, and the German Bad as in Bad Homburg, Baden-Baden, and the spa-town suffix. Bathroom is surprisingly recent — only 1780 — and bath in the sense of a measure of liquid is biblical, from Hebrew, unrelated.