Offer written evidence of the security of ownership. That is why they are called securities. A share gives the holder the right to own property, which he may not physically possess at the time.  These are securities that represent some sort of ownership interest in a company. Shares of stock are the most common form of equities traded on an open market. There is a degree of constancy about the long-term, inflation-adjusted returns on stocks. 
Shares, the instrument through which the equity market operates, are liquid, and can normally be bought and sold at any time.  They allow people to invest “passively” in ventures over which they had no direct control.  Over the long term the returns on stocks are so stable that they are actually safer than even government bonds or treasury bills.  Investors who cannot afford to wait for better returns in the long term may have to sell their shares at a loss.  But equities build wealth out of savings over the long term. 
Stocks are better than bonds or bank deposits because investing in profitable businesses is likely to have a better investment yield than lending to such businesses, which is what banks and bond issuers do.  The value of things held by companies rise, in order to keep pace with inflation. Since companies can rise the prices of the goods and services they sell, their earnings keep up with inflation.  If returns were adjusted for inflation from 1802 to 2001. $1.00 invested in stocks would have returned $599,605.00 while bonds and bills would have returned $952.00 and $304.00. The results for investments in gold and the US dollar would have resulted in losses, since that $1.00 investment in gold would have been reduced to 98 cents and the US dollar only seven cents. 
14c equal uniform, identical, equal, level, even, just," of unknown origin. Parallel formation was in use late 14c.-17c. 
15c equate level, levelled, even, make even or uniform, make equal, level, even, equal." Earliest use in English was of astrological calculation, then "to make equal;" meaning "to regard as equal" is early 19c.