Here are some possibilities:
* "boll" - This root is related to "bulge" and refers to a round, swelling part. You might find it in words like:
* Boll weevil (a beetle that damages cotton bolls)
* Bollworm (a caterpillar that damages cotton bolls)
* Bollard (a post used to prevent vehicles from entering a certain area)
* "bole" - This refers to the trunk of a tree.
* "boll" - This word is related to "bowl" and refers to a round, hollow vessel.
* "bold" - This word refers to courageous or daring. While not directly related to the root "bol," it sounds similar.
If you can provide some context or the word you are thinking of, I can help you find the correct root.