A dividend is where a company decides to distribute some of their profits to shareholders. It is a way for the company to reward their shareholders for investing in the company. Dividends can be either regular (usually declared and paid quarterly), or special (where companies want to pay extra rewards to their shareholders and are usually one-off in nature). A dividend is a zero-sum-game, as it does not affect the overal benefit you get from owning the company. If a dividend of $0.10 is declared, generally the share price will decline by $0.10.
Nanovest shows this information on stock screen as number of dividend received by user. E.g., if you received a $50 dividend from Apple during your investment, you could see this $50 value on the transaction history as dividend entry.