Wax Pack: Your basic pack of cards. From the 1930s up to 1991, most cards were packaged in a wrapper that was basically wax paper, with a hot roller used to seal it. Since wax stains greatly lower the condition and value of affected cards, this method fell out of favor as the market went upscale. Upper Deck introduced the fin-sealed foil pack in 1989, and within a few years, everyone followed suit. The term "wax pack" is still in use today, even though actual wax-sealed packs are long gone.
Since a wax seal is easily broken and resealable, caution should be taken in purchasing older wax packs because they may have been pack searched. There are some dead giveaways, such as browning on the pack seal. Such browning may come from an unskilled fraud using too hot an iron to re-melt the wax and thereby burning the paper. Also, if you open your pack and find wax stains on cards in the middle of the pack, or cards from a different series, you got screwed.