Final answer:
The word 'united' demonstrates that the 13 colonies agreed to be independent from Great Britain, as it is prominently featured in historical documents from that era.
Step-by-step explanation:
The word that indicates that the 13 colonies were all in agreement regarding independence from Great Britain is 'united.' Throughout the documents related to the colonies' independence, including the Declaration of Independence and the Articles of Confederation, there is a reiterated theme of unity and collective action. It is evident in phrases such as 'We therefore, the Representatives of the united States of America, in General Congress, Assembled,' which underscore the colonies' commitment to act as a single entity, unified in their purpose to establish themselves as free and independent states. The Declaration made it clear that this unity was not just political but also personal, as the signatories pledged their lives, fortunes, and sacred honor to support this declaration of independence.