The Base Set Things (as well as a number of Common Things) have text following each icon in the Thing's ability information. This is to help new players become familiar with the iconography used in Mythical to describe game terms like Mana, Acquires, and Resources.
This "helper" text is only available for Base and Common things. It can be turned off via the Settings Menu using the "More Settings" button.
Here is an example using the Unicorn, with the text on and off:
Due to the limited space in the ability text, Mythical uses icons when possible. However, this is one the biggest barriers when learning to play Mythical. Players can always click on a Thing to get a more detailed description (with the "helper" text), but this can be inconvenient.
Here is the detailed view for the Unicorn:
Also, the tutorial is also a great way to learn about the meaning of the game's icons, too!