Does the closing price reflect the last transaction of the stock?

Closing price generally refers to the last price at which a stock trades during a regular trading session. For many U.S. markets, regular trading sessions run from 9:30 a.m. to 4:00 p.m. Eastern Time. 

The last traded price (LTP) usually differs from the closing price of the day. This is because the LTP represents the actual last traded price, while the NSE's closing price is calculated as a weighted average of the last 30 minutes of trading.