close
Close of the current bar. Default source for ema(9) and similar.
Reference/Price series/Series
close
Most moving averages and oscillators use close when you omit the series argument. close 1 bars ago (or close[1]) is the previous bar. As an action word, close means exit — use it only inside a when body, not as a price.
Return value
series
Example
when close is above ema(21) then buy