1
general::
1. For all practical purposes, as in This testimony in effect contradicted her earlier statement. [Late 1500s] 2. In or into operation, as in This law will be in effect in January. Related phrases include go into effect and take effect, which mean "become operative," as in This law goes into effect January 1, or It takes effect January 1. Similarly, put into effect means "make operative," as in When will the judge's ruling be put into effect? [Late 1700s] Also see IN FORCE, def. 2.
American Heritage Idioms
2
general::
Phrase(s): in effect
producing a particular effect; effectively. • In effect, this new law will raise taxes for most people. • This policy harms domestic manufacturers. In effect, all our clothing will be made in foreign countries.
McGrawhill's American Idioms And Phrasal Verbs