To actualize something is to accomplish or complete it. It is always used with an object. British English spells it actualise.
The spelling change extends to all forms (e.g., actualises, actualizes, actualised, actualized, actualisation, actualization, actualising, actualizing).
A related term is self-actualized (self-actualise) which means to accomplish or complete oneself to your fullest potential. It has all the same forms as actualize and all the same spelling variations.
It could be the chance many freedom lovers have been waiting for to actualize the Constitution’s potential for protecting free interprovincial commerce and economic liberty. [National Post]
Not to actualise the disaster, to make it real, feel it, process it and resolve it, but to remove it, package it, give it a framework that is manageable somehow. [The Guardian]
Aspiring singers and vocal students are urged to “…Honor the song” and “become the subject.” John Venables actualizes these principles to a remarkable degree in his chosen role as an “Alaska History Storyteller.” [Delta News Web]
Modi’s actions can be seen as an actualization of Singh’s vision of economic liberalization. [National Interest]
Even if every country in the world but Israel calls it the state of Palestine, a negotiated settlement is a necessary step to the actualisation of independence. [Gulf News]
That bothered Giselle Jones-Jones, a High Point native who last year published a book about the woman’s journey and its relation to the contemporary pursuit of black women toward becoming self-actualized. [HPE]
And Tommy is living the mid-life dream, mining for meaning by shocking himself out of complacency, the next step in Tommy Tiernan’s journey of self-actualisation, a journey that becomes more interesting all the time. [Irish Independent]