A horse opera, hoss opera, oat opera or oater is a Western film or television series that is clichéd or formulaic, in the manner of a (later) soap opera or space opera.

https://en.m.wikipedia.org/wiki/Horse_opera#:~:text=A%20horse%20opera%2C%20hoss%20opera,soap%20opera%20or%20space%20opera.

The term, which was originally coined by silent film-era Western star William S. Hart, is used variously to convey either disparagement or affection. The term “horse opera” is quite loosely defined; it does not specify a distinct sub-genre of the Western (as “space opera” does with regard to the science fiction genre).

On Saturday Night, HEARTLAND is showing a 1938 Western starring Roy Rogers. And in every Movie I have ever seen with Roy Rogers starring, he Sings in them. Singing to his Horse or his Love in the Movie. That’s why a Horse Opera, I believe, must have a Singing Cowboy or Singing Cowboys in that Movie or TV Show. Thus Opera and they usually sing on horseback.

“Horse opera” is definitely linked to singing cowboys like Roy Rogers. Here’s what I dug up:

• Origins: The term “horse opera” goes back to the silent film era, coined by Western star William S. Hart. It can be used seriously or jokingly.
• Meaning: It doesn’t have a single, strict definition. Sometimes it’s used critically, implying the films are cheesy or melodramatic. Other times, it’s used affectionately, highlighting the adventurous and sometimes musical aspects of these Westerns.
• Connection to Singing Cowboys: This is where things get interesting. Singing cowboy movies, like those Roy Rogers starred in, are a big part of the “horse opera” world. These films often featured showdowns, chases, and clear-cut heroes triumphing over villains, all wrapped up with musical numbers. The singing cowboy serenading his horse or belting out a tune while riding might be part of the charm (or cheesiness, depending on your view) that led to the “horse opera” label.

Here’s some additional info:

• Genre vs. Trope: Unlike “space opera” which is a sub-genre of science fiction with specific conventions, “horse opera” isn’t a distinct sub-genre of Westerns. It’s more like a descriptive term capturing certain elements, especially the focus on action, music, and sometimes a more lighthearted tone.
• Evolution of the Term: The use of “horse opera” has changed over time. Back in the day, it might have been more critical. Today, it’s often used with a touch of nostalgia for those classic singing cowboy films.

So, to sum up: “Horse opera” is a way to describe Westerns, often starring singing cowboys like Roy Rogers, that emphasize action, music, and sometimes a simpler good-versus-evil storyline. It can be a playful or critical term, depending on the context.