A dividend is profit handed back rather than reinvested. The dividend yield is the annual payment divided by the share price, so the yield rises automatically when the price falls, which is worth remembering before treating a high yield as a bargain.
Four dates govern it. The declaration date announces it, the ex-dividend date is the cutoff after which a buyer does not receive it, the record date fixes the register and the payment date delivers the cash. The share price typically opens lower by roughly the dividend amount on the ex-date.
Consistency is the signal, not size. US companies treat dividends as close to a promise, so boards raise them cautiously and cut them only under real pressure. A cut is one of the clearest admissions of trouble a management team ever makes.