Sentence:  <WSD>Speculation</WSD>, while confined within moderate limits, is the agent for equalizing supply and demand, and rendering the fluctuations of price less sudden and abrupt than they would otherwise be. 
Meaning of the word marked with <WSD> tags:  The act or practice of buying land, goods, shares, etc., in expectation of selling at a higher price, or of selling with the expectation of repurchasing at a lower price; a trading on anticipated fluctuations in price, as distinguished from trading in which the profit expected is the difference between the retail and wholesale prices, or the difference of price in different markets.