What is standing room only at a baseball game?

Also question is, what does it mean by standing room only?

An event is described as standing room only when it is so well-attended that all of the chairs in the venue are occupied, leaving only flat spaces of pavement or flooring for other attendees to stand, at least those spaces not restricted by occupancy by fire codes for ingress/egress of crowds.

Similarly, where is standing room only at Wrigley? There are no specific standing-room-only sections at Wrigley Field. Instead, the tickets grant you access to the entire horseshoe of the "Terrace reserved" area, which is the midlevel walkway situated above the lower level seats and sheltered by the upper deck.

In respect to this, what is standing room only at Yankee Stadium?

There are standing room only tickets at Yankee Stadium, meaning that you will not have a designated seat to watch the game. There are both Field Level and Terrace Level standing room tickets, so fans stand somewhere in the concourse on one of these two levels when you have a standing room only ticket.

How is standing room only at Cowboys Stadium?

A Standing Room Only (SRO) ticket gives Dallas Cowboys fans the chance to participate in the Cowboys game day experience. The Standing Room Only ticket gives fans access to six decks to stand and watch the game from inside AT&T Stadium, and does not grant access to a physical seat or seat location.