[vuroth]

Playing in an indy, only agreement is SAYC/Std Carding.

P 1♣ 1♠ 2♦
P 2♠

What is 2 spades?

[TylerE]

Without discussion I would take it as a strong hand with no obvious bid. Something like a balanced 18-19 with no stopper for instance.

[awm]

It shows a strong hand, creating a game force.

It could be any of:

(1) Extras (like 15+) with long clubs (doesn't want to bid 3♣ because partner could pass)
(2) Balanced 18/19 with no spade stopper.
(3) A strong diamond raise (doesn't want to bid 3♦ because partner could pass)
(4) Balanced 18/19 with a dubious spade stopper like Ax (direct 3NT too unilateral)

The main point after this bid is just to keep bidding naturally, but remember that you are now forced to game.

[hotShot]

In an BBO indy one has to consider that 1♠ may have been a psyche.

Otherwise 2♠ is a strong forcing bid and partner will tell you more next round of bidding. Usually he will not have biddable ♥ and wants to know more abut your hand.

[P_Marlowe]

Forcing, most likely to game, asking for further description,
mainly for a spade stopper.

With kind regards
Marlowe

[Califdude]

Asking for a spade stopper.

[peachy]

Game force. A strong hand that did not want to make a bid that partner can pass if partner is minimum. Even though a 2/1 responding hand promises another bid in SAYC, it does not always happen and there are some who allow Pass with minimums. The "strong" opener can be lots of HCP (looking for NT most likely), offensive with good fit for diamonds (will show it next round), or strong one-suiter in clubs (will show it next round), for example. Responder should keep describing his hand.