It took looking it up to realize that insect has the same root as bisect, dissect, and intersect, and I guess I just never knew that bit of information.
What are some other words that share the same root that don’t seem to fit, or at least you have to read the etymology to see the connection(s)?
Since it will probably go in that direction anyway, you can also include those words that share spellings even if they’re not directly from the same roots.
Stuff like: butter and gutter and clutter.
“lactating” & “galaxy”
But not “prophylactic” and “parallax” (just think if they were what “breasts” might be).
“partridge” and “fart”
Very and veritable
Oddly enough “cartridge” and “cart” seem to apply here.
“Poppycock” and “poop.” I can’t really enjoy the snack food the same way, knowing it literally means “soft stool.”
Wait a minute? Cock means SOFT?
No, relax, it’s not that bad. 
What about “murmur” and “murder” and “Murphy’s Law”? Would “mermaid” and “Merman” go in that group or a separate one?
“Murmur” goes back to Latin “murmurare”; “murder” goes back to Germanic roots – I don’t think they are related.
They are connected fairly trivially. and the “mer-” is related to Latin “mare” and German “Meer”, so it’s a different group. Words they are connected with include “maritime” and “submarine”.
The connections here are not sounds, but word origins.
When you hear the call to prayer from the minarets of a mosque, it might seem to sound like a mosquito. :smack: No connection, though.
The little toasted pieces of bread called panetini sounds like it ought to refer to little panties. Nah, it’s little breads. Come to think of it, there may be yeast in both.
*Congregation, gregarious, and egregious * all come from a root meaning “herd.”
“Pencil” and “penis” are etymologically linked.
Heck, pencils even have rubbers on 'em. How about that?
Astonish and thunder.
No, really.
Slight hijack. Bear in mind that all pronunciations are British!
Back in the day I was taking notes during an extremely interesting English lecture on the Roots of Language. It covered the origin of certain words in medieval texts and their impact on both older and newer texts.
Toward the end there was a slight pause during which the class were conversing and my neighbour and I enthused about what a fantastic subject today’s lecture had been. Until I happened to look at my neighbour’s notes and discovered that she had not in fact been in the same lecture. No, she’d heard one about the ‘Routes of Language’. This lecture covered the journey of certain words from medieval texts and explained how they got to be included in newer texts even though they were archaic.
Seeing our consternation the lecturer asked if there was a problem. We explained and asked which spelling he had meant R-O-O-T-S or R-O-U-T-E-S. He mused and decided not to tell us since both words worked well for the subject and actually provided a more rounded picture depending on which word we used. 
The one I found out recently was that “guest” and “host” have the same root - making them really two sides of the same coin.
I bet you feel more comfortable now that you know cock actually means dung.
And the study of insects is entomology, which is the Greek version of the same concept – having a notch “cut” in the waist.
So we have the atom, a particle that can’t be cut into pieces (at least that’s what Dalton thought).
And all those surgical procedures – like appendectomy, mastectomy, lobotomy – have the same reference to cutting.
“Tome” also has the same root, as it originally meant not just a big, scholarly book, but a volume or section of a book that had been cut out of a larger work.
And “epitome” originally meant an abstract or abridgement – a work that had been cut down. The meaning of “person or thing that typifies something” came later.
Right, and they’re related to hotel / hostel and hostile.
Gentle and gentile (but not genital).