Common land description terminology

Calif. start­ing points for land descrip­tions using U.S. Gov. Rect. Sur­vey Sys­tem:
A rec­tan­gu­lar sys­tem of land sur­vey that divides a dis­trict into 24-square mile quad­ran­gles from the merid­ian (north-south line) and the base­line (east-west line); the tracts are divided into 6-mile-square parts called town­ships, which are in turn divided into 36 tracts, each 1 mile square, called sec­tions.
4. Know land sizes; how large is a:
sec­tion — 1 sq mile
acre One acre com­prises 4,840 square yards or 43,560 square feet.[1] While all mod­ern vari­ants of the acre con­tain 4,840 square yards, there are alter­na­tive def­i­n­i­tions of a yard, so the exact size of an acre depends on which yard it is based on. Orig­i­nally, an acre was under­stood as a selion of land sized at one fur­long (660 ft) long and one chain (66 ft) wide; this may have also been under­stood as an approx­i­ma­tion of the amount of land an ox could plough in one day. A square enclos­ing one acre is approx­i­mately 208 feet and 9 inches (63.6 metres) on a side. But as a unit of mea­sure an acre has no pre­scribed shape; any perime­ter enclos­ing 43,560 square feet is an acre in size.

5. What are the rec­og­nized legal meth­ods of land descrip­tion:
rec­tan­gu­lar sur­vey
meets and bounds
lot and block num­ber
mon­u­ment or occupancy

6. Another ques­tion regard­ing the size of land; ½ a sec­tion has how many acres, ¼ sec­tion, etc:
Since 1 sec­tion has 640 acres — 1/2 a sec­tion would be 320 acres