One-liner: Wiki thinks its the same. Although Wiki is not always perfect about information it posts, the justification there make sense to me.

Looked up at [Heat Index wikipedia](https://en.wikipedia.org/wiki/Heat_index), it says, 

> The heat index (HI) or humiture is an index that combines air temperature and relative humidity, in shaded areas, to posit a human-perceived equivalent temperature, as how hot it would feel if the humidity were some other value in the shade. The result is also known as the "felt air temperature", "apparent temperature", "real feel" or "feels like"

Quoting other source such as [weather.gov](https://www.weather.gov/ama/heatindex):

> The heat index, also known as the apparent temperature, is what the temperature feels like to the human body when relative humidity is combined with the air temperature.  This has important considerations for the human body's comfort.

Additional information for those who don't know that this term means, quoting from the same source again,
> When the body gets too hot, it begins to perspire or sweat to cool itself off.  If the perspiration is not able to evaporate, the body cannot regulate its temperature.  Evaporation is a cooling process.  When perspiration is evaporated off the body, it effectively reduces the body's temperature.  When the atmospheric moisture content (i.e. relative humidity) is high, the rate of perspiration from the body decreases.  In other words, the human body feels warmer in humid conditions.  The opposite is true when the relative humidity decreases because the rate of perspiration increases.  The body actually feels cooler in arid conditions.  There is direct relationship between the air temperature and relative humidity and the heat index, meaning as the air temperature and relative humidity increase (decrease), the heat index increases (decreases).

[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/wpe9N.jpg