In co-axials, a 2-way speaker is a speaker that contains only a midwoofer and a tweeter…..the midwoofer playing the lower frequencies (down to around 80hz or so), the tweeter playing the higher frequencies (around 3khz or 4khz and up). 3-way co-axials typically have a midwoofer, tweeter and "supertweeter", with the supertweeter being designated to handle the very, very high frequencies only. Co-axials can go as high as 5-way (midwoofer, midrange, smaller midrange, tweeter and supertweeter). For all intents and purposes, anything more than 2-way in co-axials is a marketing gimmick. Going with 3-way co-axials or higher usually does not increase performance much, if at all.