Research literature terminology illustrates that publications claim to pertain to "disciplinary"approaches and researcher's align themselves to specific, multi-, inter- or trans-disciplinarities. Ambiguity exists in definition and application of disciplinarity, hence there is need to establish a coherent application of disciplinarity. We present results of content analysis of research literature claiming to be inter-, multi-, or transdisciplinary to assist in ascertaining commonalities or differences for those disciplinarities. We analyse the abstracts and keywords of 8834 papers, using n-grams and bi-grams, dating from 1970 until 2018, extracting a list of 76,552 terms for comparison. The top 15 most frequent terms characterise each disciplinarity and Venn diagrams of the top 15 features illustrate differences and overlap. A total of six terms appear common to all approaches in the abstracts, with four shared by multi- and inter-, two between inter- and trans-, and none common to multi- and trans-. The term "social science(s)"appears to be a unique feature in the trans- abstracts and our findings identify common text terms such as the "research"feature, common to all disciplinarities. This supports characterising the nature of transdisciplinarity and its unique differences from other approaches such as inclusion of social science(s).