Essentially, depreciable assets are anything bought for your business that has a useful life or more than one year. Think things like vehicles and equipment rather than supplies or consumables. For example, an industrial sewing machine would count as a depreciable asset, but not the thread.
There are some other specific qualifications for depreciable assets. If you're still unsure how to answer, consult the IRS website's section on depreciation: https://www.irs.gov/publications/p946#idm140613535290848