Where did the word "apologetics" come from?
The English word "apologetics" comes from the Greek word "apologia", translated "give an answer/defense" in 1 Peter 3:15 (cited above).
What does "give an answer/defense" in 1 Peter 3:15 mean?
Simplified, it means being able to give a logical, reasoned defense for your beliefs i.e. knowing why you believe what you believe. The purpose of apologetics is not to "win an argument", but rather to "win a person" by means of respectful, kind, intelligent dialogue where Christianity is concerned. Never forget the final phrase Peter uses here: "do this with gentleness and respect."
Who are notable Christian apologists?
The most recognized name would most likely be the former atheist, Oxford scholar, and Narnia Chronicles author, C.S. Lewis. His most-read book where apologetics is concerned is Mere Christianity. (Read more about its lasting influence here.) Other notable apologists from the early 20th century are G.K. Chesterton, Francis Schaeffer, and Dorothy Sayers, just to name a few.
Historically, notable examples would include Augustine, Anselm of Canterbury, Thomas Acquinas, and Blaise Pascal.
Notable modern-day apologists include: William Lane Craig, Lee Strobel, John Lennox, Alvin Plantinga, Paul Copan, Josh & Sean McDowell, Mike Licona, Gary Habermas, Tim Keller, Michael Behe, Andy Bannister, Nancy Pearcey, Alister McGrath, Greg Koukl, Douglas Groothuis, William Dembski, Stephen Meyer, Eric Metaxas, Frank Turek, Nabeel Qureshi, and Ravi Zacharias. Almost all of the people listed here possess PhD's in their respective fields of study. All are respected scholars among - and outside - the Christian faith.