n. pl. al·tos
1. A low female singing voice; a contralto.
2. A countertenor.
a. The range between soprano and tenor.
b. A singer whose voice lies within this range.
c. An instrument that sounds within this range.
d. A vocal or instrumental part written in this range.
[Italian, from Latin altus, high; see al-2 in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 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.