If $73429186$ denotes $\text{PURCHASE}$, and $54064$ denotes $\text{ORDER}$, then what will $7452688$ denote?

Let us extract the letter-to-digit direct mapping from the provided cipher pairs:
From $\text{PURCHASE}\to 73429186$:

* $7\to \text{P}$
* $3\to \text{U}$
* $4\to \text{R}$
* $2\to \text{C}$
* $9\to \text{H}$
* $1\to \text{A}$
* $8\to \text{S}$
* $6\to \text{E}$

From $\text{ORDER}\to 54064$:

* $5\to \text{O}$
* $4\to \text{R}$
* $0\to \text{D}$
* $6\to \text{E}$
* $4\to \text{R}$

Now, mapping the target sequence $7452688$:

* $7\to \text{P}$
* $4\to \text{R}$
* $5\to \text{O}$
* $2\to \text{C}$
* $6\to \text{E}$
* $8\to \text{S}$
* $8\to \text{S}$

Combining these gives the word PROCESS.