Commonalities

What do the words in each group have in common?


1.
doughnut
notebook
golf course


2.
sport
rain
top


3.
turtle
peanut
oyster

4.
brown
polar
Kodiak


5.
cough
tear
rain

6.
soap
granola
candy

7.

tick

lift

end

8.

docent
daring
demoted
kink
moving
argent
pond
tended

I'll post the solution on the 16th.