Exchange
Part of speech: noun
Definition: An act of exchanging or trading. A place for conducting trading. (telephony, US only?) The fourth through sixth digits of a ten-digit phone number (the first three before the introduction of area codes). A conversation.
Part of speech: verb
Definition: To trade or barter. To replace with a similar item.
Example sentence: With so many ways to communicate at our disposal, we must not forget the transformative power of a live music experience and genuine human exchange.
Substitution
Part of speech: noun
Definition: the act of substituting or the state of being substituteda substitute or replacement(especially in organic chemistry) the replacement of an atom, or group of atoms, in a compound, with another
Example sentence: I'd like to think I am a good coach but I've called bad plays. I've coached bad practices. I've made bad substitution choices.