"Oar" is a noun referring to a long, flat blade used for rowing a boat.
"Derivatives" are words that are formed from other words.
Therefore, "Oar Derivatives" would refer to words derived from the word "oar", which might include:
* Oared: past tense and past participle of "to oar"
* Oaring: present participle of "to oar"
* Oarlock: a device that holds the oar in place
* Oarman: a person who rows a boat
* Oarsman: a person who rows a boat
Please let me know if this is what you were looking for, or if you had something else in mind.