This senior honors thesis investigates color terms and the expression of color in the Korean language. Korean was chosen as the language to be investigated for two reasons: first, there have been very few studies that investigate the expression of color and second, the existence of an adjectival category (and, as a corollary, are Korean color terms adjectives) is a controversial issue. In addition, Korean linguists have posited the theory that there is a single color term that encompasses the colors blue and green; this has come to be known as the “gru” phenomenon. Previous studies have not included detailed investigation into the usage of different color terms in Korean, especially with respect to the “gru” phenomenon. The investigation in this thesis will look into the three forms of Korean color terms: Native Korean terms (such as the words “ppalgan” for red, and “kkeuman” for black), borrowed Chinese terms (such as “bunhong” for pink, and “baek” for white), and borrowed English terms (such as pink, orange). The two main research questions pursued in this thesis are: first, is there evidence for the existence of the “gru” phenomenon in the Korean language? Second, are Chinese borrowed color terms undergoing replacement with English color terms in the higher levels of color hierarchy in the Korean language? The methodology used in this thesis is a Qualtrics survey with tools from psycholinguistics. Participants were asked to do a forced choice elicitation task as well as a fill-in production task. Eight native Korean speakers participated in the survey. The results of the study indicate that while English loanwords are acceptable and utilized, the subjects have a strong preference for the older Chinese borrowed roots. The “gru” phenomenon is not corroborated by the preliminary study results. This investigation raises additional avenues for future research. Is the “gru” phenomenon limited to natural objects (e.g., frogs, plants, fruit-bearing trees)? Has the Korean language evolved away from the “gru” phenomenon? Is the “gru” phenomenon actually a reference to a specific blue-green color (if so, this would have ramifications for theories of color term evolution in languages)? Do Korean color terms support or negate the existence of an adjectival category in the Korean language?