1. In addition; besides.
2. Likewise; too: If you will stay, I will also.
And in addition: It's a pretty cat, also friendly.
[Middle English, from Old English ealswā : eall, all; see al-3 in the Appendix of Indo-European roots + swā, so; see SO1.]
Usage Note: Some people maintain that it is wrong to begin a sentence with also. In our 2014 survey, however, 70 percent of the Usage Panel found the usage acceptable in this example: The warranty covers all power train components. Also, participating dealers back their work with a free lifetime service guarantee. Given this high rate of acceptance, as well as the fact that it is perfectly normal to start sentences with other conjunctive adverbs such as furthermore, there seems no reason to condemn this usage of also.
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.