Sorry I don't usually follow the Flyers, but love their team.
What exactly is a "Peco"
Its a Flyers powerplay. At home games our powerplays are sponsored by a power company named Peco, so when there is a Flyers home PP the PA announcer will say "and the Flyers are going on the PECOOOOOOOOOOO POWERPLAY!" So it carried over to this site.