1. Toward or closer to the source of a stream; in the direction opposite to that of the current: paddling upstream.
2. At an earlier point in a production process or supply chain.
1. Being or moving closer to the source of a stream; in the direction opposite to that of the current: upstream traffic; an upstream dam.
2. Earlier in a production process or supply chain.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2020 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.