Alternate explanation:
Hormone: Pretty much any chemical your body uses for intra-body signaling. Signaling in this case can be anything from dumping adrenaline in order to move blood preferentially to the muscles, to the production of estrogen in order to promote cell growth in certain organs.
Steroid: A particular class of compounds grouped by the existence of a particular quartet of carbon atom rings inside each of the molecular structures. They have a very wide range of roles across the tree of life. Examples include, but are not limited to: testosterone, cholesterol, ergosterol, and progesterone.
Steroid (colloquial meaning): Pretty much any performance enhancing drug, including hormones and actual steroids.
In this case, nothing. High dose testosterone is a hormone, hgh is a hormone. Both are PEDs (performance enhancing drugs). Now, the difference between them is a bit more interesting.
Testosterone, the original steroid, makes you big by maximizing your existing muscles (super paraphrased, as is everything I’m about to say). It’s the one that gives you breasts and shrinks your balls (for those that have them).
Human growth hormone makes you big by inducing the creation of new muscle. As well as everything else. The stand outs being the heart, which you really don’t want to grow, and the intestines, which gave bodybuilders roidgut.
Like I said, very paraphrased, but that’s the gist of it. And doesn’t touch more advanced things like tren.
In their definitions?
Hormones are messengers that communicate between cells around the entire body, and are typically released into the blood to be distributed (thus their systemic effects). This is in contrast to communicative messengers that specifically target a cell, such as neurotransmitters, or paracrine messengers, which pass signals from a cell to other nearby cells.
Steroids are one example of hormones, and are usually cholesterol derivatives. The famous steroids you are familiar with are testosterone (which has several forms) and estrogen (which has several forms). Steroids are lipid-soluble, which means they can enter your cells through the plasma membrane without needing transporters. They then interface with systems inside of your cell, and typically will cause a formed complex to move from the cytoplasm to your nucleus, where they will interface with your DNA and begin promoting a specific gene or gene series.
Other hormones include modified amino acids, such as thyroid hormone, or proteins, like insulin.
