Turtle is a format for expressing RDF data

Turtle or Terse RDF Triple Language is a syntax and format for expressing RDF data.

Turtle is a more human readable and editable alternative to the RDF/XML format.

SPARQL uses a similar syntax for expressing queries.

Example of turtle markup from https://rdf-turtle.surge.sh/index.ttl:

@prefix : <http://rdf-turtle.surge.sh/index.ttl> .
@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
@prefix schema: <https://schema.org/> .
:diagram schema:image <http://www.ldf.fi/service/rdf-grapher?rdf=http://rdf-turtle.surge.sh/index.ttl&from=ttl&to=svg> .
:sample a rdfs:Class ;
  rdfs:label "Sample" ;
  rdfs:comment "This is a sample RDFS Class." .
:animal a rdfs:Class ;
  rdfs:label "Animal" ;
  rdfs:comment "Multicellular eukaryotic organisms in the biological kingdom Animalia" ;
  schema:ImageObject [
    schema:contentUrl <https://upload.wikimedia.org/wikipedia/commons/1/14/Animal_diversity.png>
  ] .

See Resource Description Framework (RDF), Semantic triples (RDF triples).