"reciprocate" VS "respond to"

[Polyester]

I think they are same, but I'm not sure.

I think the proof from this site is explaining the same meaning.

with object Respond to (a gesture or action) by making a corresponding one. ‘the favour was reciprocated’
no object ‘perhaps I was expected to reciprocate with some remark of my own’
https://en.oxforddictionaries.com/definition/reciprocate

 

[J&K Tutoring]

To reciprocate is to respond, but not every response is reciprocal:

1. 'Will you feed my cat while I am on my trip?' 'Sure, if you can feed my dog when I go next month.' 'Okay!' That is reciprocating.

2. 'Will you feed my cat while I am on my trip?' 'No, I'm afraid of cats.' That is a response, but definitely not reciprocating!

 

[teechar]

‘perhaps I was expected to reciprocate with some remark of my own’

I can see that "respond" can be substituted for "reciprocate" in that sentence, and that may be the source of your confusion. However, note that the dictionary didn't say just "respond". It said "respond to (a gesture or action) by making a corresponding one." Look at the other example sentences in that link, and you'll find that "reciprocate" and "respond" are not interchangeable.

 

[Polyester]

Are they similar, but not the same?

 

[teechar]

Yes, can you see which one has the broader meaning?

 

[Polyester]

Is the "respond" has a broader meaning?

 

[teechar]

[STRIKE]Is the[/STRIKE] Does "respond" [STRIKE]has a[/STRIKE] have the broader meaning?

Yes, that's right.

 

[emsr2d2]

My girlfriend sent me flowers. I responded by sending her a bottle of champagne.
My girlfriend sent me flowers. I reciprocated.

In the second, it is understood that I sent flowers to my girlfriend.