- Economic nexus
- A connection to a state created by the amount of sales into it, such as $100,000, rather than by physical presence.
- Physical nexus
- A connection created by a physical presence, such as inventory, employees or property in a state.
- Marketplace facilitator
- A platform, such as Amazon or Etsy, that is required to collect and remit sales tax on orders it processes for sellers.
- Wayfair decision
- The 2018 Supreme Court ruling in South Dakota v. Wayfair, Inc. that allows states to require remote sellers to collect tax based on economic activity.
- Rooftop rate
- A sales tax rate determined at the exact delivery address instead of a ZIP code.
- Origin and destination sourcing
- Whether tax is based on the seller's location or the buyer's location.
- Streamlined Sales Tax (SST)
- An agreement among member states to simplify and align sales tax rules, including sourcing.
- Voluntary disclosure agreement (VDA)
- An arrangement in which a business comes forward to a state about unpaid tax, often limiting look-back periods and penalties.
- Look-back period
- How far back a state can assess unpaid tax. It can be several years, or unlimited if no return was ever filed.
- Resale certificate
- A document a buyer provides to purchase goods without tax because they will resell them.
- Zero-due return
- A return filed to report sales where no tax is owed by you, for example because a marketplace collected it.
- Trailing 12 months
- A rolling measurement period of the last 12 months, used by some states to evaluate thresholds.