How many times do you hear the melody in (John Powell) Test Drive?

your word would be isle.

isle is an island or peninsula especially a small one.

if you add the letter "a" you get aisle, which is a passage between 2 rows of something like chairs, shelves, or something else.

cad, or computer-aided design and drafting (cadd), is a software for design and technical documentation, which is an automated process as opposed to the manual drawing of plans. this gives a person an advance in making plans as an architect in a short period of time. one who can render plans through this software will gain a skill that is better than one who makes plans manually. this is a skill some companies look for in an employee.