What is the term for something that is steady and regular?

The term that accurately describes something that is steady and regular is "consistent." This word denotes a quality of maintaining the same principles, course, or form, ensuring that something does not vary. In contexts such as performance, behavior, or outcomes, consistency implies a uniformity that can be relied upon over time.

While stable, constant, and reliable also reflect positive attributes related to steadiness, they emphasize different aspects. "Stable" suggests a lack of change or volatility, frequently used in physical or emotional contexts. "Constant" indicates something that remains unchanged over time, often used in scientific or mathematical contexts to describe unchanging conditions. Lastly, "reliable" conveys the trustworthiness or dependability of something, suggesting that it can be counted on to perform as expected.

Thus, "consistent" is the most appropriate term when referring specifically to the regularity and steadiness of a particular condition or behavior.