Bids of 2D, 2H and 2S are 'weak', showing a 6-card suit and 5 to a bad 11 HCP, as well as NO side four card major, nor any two singletons or voids. Weak 3-bids show the same point strength, but require 7 cards.
2C is an artificial bids showing a very strong hand. Many players reserve 2D as another type
of artificial bids (e.g., Multi-2D, Mini-Roman).
The preempt bidder DOES NOT bid again unless forced by partner. Any suit bid by partner is one-round forcing. If the partnership plays FEATURE, OGUST, or some other systemic procedure, 2NT may be forcing or invitational. Raising the suit one level usually is preemptive, though many partnerships play it as invitational (usually, partnerships that do not play 2NT as an asking bid).
S: xxx H: Kxx D: xxx C: Kxxx S: x H: AQTxxx D: xx C: Qxxx W N E S 2H P 3H P/O Note: The 3H bid in this case was preemptive, making it risky for a strong east to make a takeout double; opps have a spade and