thickness

The story

1. Proto-West Germanic · inherited from*þikkwīnassī“thickness”
2. Old English · inherited fromþicnes“thickness, viscosity, density, hardness; obscurity, cloud, darkness; thicket; depth, a thick body, anything thick or heavy”
3. Middle English · inherited fromthikkenesse
4. English todaythickness

From Middle English thikkenesse, thiknesse, from Old English þicnes (“thickness, viscosity, density, hardness; obscurity, cloud, darkness; thicket; depth, a thick body, anything thick or heavy”), from Proto-West Germanic *þikkwīnassī (“thickness”), equivalent to thick + -ness. Cognate with West Frisian tsjokkens (“thickness”), Old High German dickinessī, dikkinissi, diknissi (“thickness, density”). Eclipsed non-native Middle English crassitude (“thickness”) from Latin crassitūdō (“thickness”).