ירך המזבח (side of the altar) – the nouns פנים (face), אחור (back), כתף (shoulder), שכם (shoulder), צד (side), ירך (thigh) are borrowed from the body of a human to the altar, which had no limbs.

And with respect to a house, there is a difference between 1) a house in which its length is greater than its width and has before it a courtyard; then the courtyard is called a פנים, the two sides are called כתפי הבית, the parts of the house that are close to the west are called ירכתי הבית, and the western side is called an אחור.

And 2) a house with a square shape; then its western side is called a ירך.

And the altar had its ramp in the south. The southern side of the altar was called פני המזבח, while its northern side was called הירך.