A maturity indicator is a measurable aspect for a FAIR (sub)principle that evaluation approaches can use. From this definition, it can be inferred that a maturity indicator should describe a self-contained aspect of the (meta)data and provide information on how it should be represented, measured, and assessed from the FAIR point of view. The definition of a maturity indicator can be implemented in different ways, from textual descriptions to semantic formats that both humans and machines can consume. Since this work aimed at automating the process of reusability assessment using maturity indicators, it was of great importance to choose a machine-readable definition format. Moreover, two primary design considerations were embraced when defining the maturity indicators. First, the metrics themselves and the applications developed around them should be FAIR. Second, they should stay up to date with proper versioning and provenance information. For the reasons mentioned earlier, Wilkinson et al. specification was chosen as the base to express the selected lists of MRS as reusability maturity indicators (under FAIR principle R1.3). However, whenever needed, it was adapted to accommodate the requirements of the nanosafety domain. In the original specification, the user fills the maturity indicator's Markdown template, which can be automatically converted to the nanopublication version using a specific software. However, this approach was adjusted in this work, so the fields of the Markdown template were extracted, and a Java properties file, a simple key-value text file, was created, and the extracted fields were used as keys in it. This properties file served as a template to fill in the necessary information when defining each maturity indicator. Later, this properties file can be converted to any other template like Markdown or Nanopublication RDF. Another convention was enforced in the MI definition process regarding what must be provided for the measurement and how the measurement is executed. Originally, those criteria Fig. JSON-LD snippet of a good example to report measured variables metadata for a nanosafety dataset using the schema.org vocabulary were flexible and can be described in any way by the user, who can later provide a coded compliance test to perform the evaluation. However, in this work, JSON-LD was explicitly chosen as the representation format of the assessed digital resource's metadata. That means, if the digital resource does not use JSON-LD format to represent the metadata, then it will not be qualified to pass the reusability evaluation for any of the maturity indicators. JSON-LD is a lightweight linked data format to easily read and write structured data on the web using open vocabularies like schema.org and bioschemas.org .