Pique Knit Fabric – The textured “bumpy” knit fabric that most Polo style shirts are made of.
Jersey Knit Fabric – A smooth finish knit fabric.  Similar to the way T-shirts feel, usually thicker for golf shirts.
Interlock Fabric - A smooth finish fabric like Jersey Knit, but softer feeling, and usually thicker.  Most of the time this is woven with combed cotton
Cool Weave or Resort Weave Knit Fabric – Like a Pique Knit, except the texture is more exaggerated to allow more air to flow, keeping you cooler.
Herringbone Fabric – A knit fabric that is woven into a herringbone pattern.
Combed Cotton – A softer feel, the cotton has been combed to straighten the fibers before spinning the yarn.
Ringspun Cotton – Smoother finish, softer feel, The cotton has been combed and spun tightly before spinning the yarn.
Mercerized Cotton – The fibers have been chemically treated in order to be very smooth & soft – sometimes even shiny.  Double Mercerized is even softer.
Jacquard - A pattern (usually "busy") in the weave of the fabric using dark and light colors.  Usually knit into the material.  There are many types of jacquard patterns, including birdseye, sawtooth, plaid, diamond, double herringbone, triangle, and arrowhead.  If no pattern is specified, it is usually a very small birdseye type pattern.
Birdseye Jacquard - A type of pattern where dark and light fabrics are woven to form a very small checked type pattern.
Drop-Needle - A weaving technique which produces indented lines in the fabric, usually to form a pattern or tone-on-tone striped effect.
Ribbed Fabric - Fabric with a ribbed pattern.  This can be very narrow, or up to 1/4" wide.
Pre-Shrunk – Most  shirts come pre-shrunk even if it’s not stated on tag.
100% Cotton: All cotton
50/50 or 60/40 : Percentage of Polyester/Cotton respectively.
Ounces – As it pertains to a shirt - is the heaviness of the fabric.  The heavier the fabric, the higher the number.  This does not necessarily indicate how strong the shirt is because the type of fabric and how the fibers are spun determine durability.

In general the ranges for most types of shirts are:
Tee Shirts: 4.0 oz. – 7.0 oz
Golf shirts: 5.0 oz. – 8.5 oz. 
Sweatshirts: 7.0 oz - 12 oz. 
Twill shirts or Dress shirts: 4.0 oz. – 6.5 oz.
Denim Shirts: 5.0 oz.  – 8.0 oz.
Fleece & Flannel: 8.0 oz. – 14 oz.

Full Cut – Usually cut fuller in hips and arms ½ - 1 size larger than normal.
Golf Cut – Usually cut fuller over all, especially in arms to allow swinging of a golf club 1 – 1 ½ sizes larger than normal.
Placket – The part of the shirt where the buttons are.
Box – The bottom of the placket.
Welt Cuffs & Collar – A knit collar & cuffs.
Tubular body – Fabric is woven into a tube – Shirt has no side seams.
Double-Stitched Seams – Seams are stitched in 2 rows for reinforcement .
Taped Collar or Seams – A strip of fabric (tape) covers the seam to reduce wear to the seam.
Side Vents – The bottom hem of the shirt is split on each side to allow it to be wider at the bottom.
Drop Tail – The bottom hem of the shirt with side vents is longer in the back than it is in the front (to prevent “Plumber’s Gap)
Locker Patch or Half Moon Patch– An extra piece of material is sewn on the back under the collar to prevent wear when the shirt is hung on hooks.
Jacquard - A pattern, usually found on the collar or cuffs that resembles a very fine checked type pattern.
Birdseye - 
Pearlized or Horn buttons – Shiny pearl-looking buttons – usually white unless specified.
Wood-tone Buttons – Brown buttons that are uneven in color fading to a khaki color on one side.