Amortization allocates the cost over the useful life of an intangible asset (trademarks, patents, etc.). It is sort of like depreciation for fixed assets which are tangible assets like (machinery, inventory, etc.). This allocation is spread equally through out the useful and estimated life of the intangible asset.
Example:
Adequate Disclosure, Inc. has a patent worth $150,000 with an estimate life of 8 years. What is the amortization expense for the first year?
$150,000/8 = $18,750