A fine-grained grey rock that splits into flat sheets.

Slate comes from Old French 'esclate,' meaning a fragment or splinter, related to a verb meaning to split. The word reflects the rock's key property of cleaving into smooth, flat pieces. It has been used in English since the medieval period.

To breathe noisily through the nose and mouth while sleeping.

Snore is thought to be imitative, echoing the rumbling sound itself. It is related to 'snort,' which describes a similar forceful nasal sound. Comparable imitative words for the same sound exist in several other Germanic languages.