dottle

[dot-l] /ˈdɒt l/
noun
1.
the plug of half-smoked tobacco in the bottom of a pipe after smoking.
Also, dottel.
Origin
1815-25; dial. dot small lump (probably identical with dot1) + -le
British Dictionary definitions for dottle

dottle

/ˈdɒtəl/
noun
1.
the plug of tobacco left in a pipe after smoking
Word Origin
C15: diminutive of dot lump; see dot1