Hi Nicole,
Within covalent bonds, there are also hierarchy in terms of how strong those bonds are. You are not expected to have this table memorized, but here it is in case you are curious:
http://gr.xjtu.edu.cn/c/...amp;name=DLFE-39601.pdf
The higher the bond enthalpy is, the stronger the bond. In general, if there is a large electronegativity difference, the bond will be slightly stronger. You can see that when comparing fluorine bonds against other atoms, or comparing atoms bonding to itself.
I think that you might be asking about a specific question or definition you may have seen. If you are able to, could you please let me know what question or page number of what resource you were looking at, and I will be able to better tailor my responses to your question.
Hope this helps, happy studying!
Molly