The function of the phrase "in turn"

@Tony C posted:

a. What is the role/function of the phrase "in turn" in the sentence below? Preposition, conjunctions?

b. What is the best replacement word for "in turn" in lay terms for the sentence below?

example: As the case for most of the employee shares, he cannot exercise the options straight away, rather these options only vested and in turn became exercisable over a 4 year period after he became an employee.

Hi, Tony—"In turn" is not one word. It is two words. Together they form a phrase—a prepositional phrase, in which "in" is a preposition and "turn" a noun (the object of the preposition). The phrase has a rhetorical usage, which you are seeing in your example. Below is a definition of the phrase from The Oxford English Dictionary (OED). I have highlighted the especially relevant portion:

Quote:

b. Phrases.  (a) by turns (also †by turn), one after another in regular succession; successively, in rotation.  (b) in turn, in turns, each in due succession: = (a). (in turn is also used rhetorically like in one's turn: see 28b(c).) (c) in one's turn, in one's due order in the series. (Often also used rhetorically to indicate an act duly or naturally following a similar act on the part of another, but without the notion of pre-arranged succession.)

Thanks David, I now understand. But what do you mean by a "rhetorical usage"?

@Tony C posted:

But what do you mean by a "rhetorical usage"?

Hi, Tony—With "rhetorical usage," I am referring to the phrase's customary use in discourse, to indicate that one thing naturally follows another. As the OED puts it, the phrase is "used rhetorically to indicate an act duly or naturally following a similar act on the part of another, but without the notion of a pre-arranged series."