Definition of "obligate" []

• To bind, compel, or constrain by a social, legal, or moral tie. See Synonyms at force. (verb-transitive)
• To cause to be grateful or indebted; oblige. (verb-transitive)
• To commit (money, for example) in order to fulfill an obligation. (verb-transitive)
• Biology Able to exist or survive only in a particular environment or by assuming a particular role: an obligate parasite; an obligate anaerobe. (adjective)
• Absolutely indispensable; essential. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Because these probes remain obligate tetramers, they are not the best choice for labeling proteins."
• "Recovery Act deadline to "obligate" - or commit to specific projects - 100 percent of their highway Recovery funds."
• "Transportation Secretary Ray LaHood announced that every state and the District of Columbia met the March 2 Recovery Act deadline to "obligate" - or commit to specific projects - 100 percent of their highway Recovery funds."