"Initial" is a formal word that means "at first" or "beginning". The "initial results" of an ad campaign means the results in the first few weeks or months.

Here are some nouns that often appear together with "initial":

• (someone's) initial reaction

  My initial reaction was, "That's the dumbest thing I've ever heard." But then I heard about it some more, and it started to make a bit of sense.

• the initial stage of (something)

  In the initial stage of the disease, you may notice a bit of memory loss and lower coordination.

• the initial cost of (something)

  The money you'll save over the lifetime of the machine will more than make up for the initial cost.

• (one's) initial impression

  What's your initial impression of her?