releaser / releasor [rəˈli:sɜr]
releaser – n. – 1. one who sets free (in various contexts); 2. farming – part of a milking machine with allows for milk to be removed; 3. zool. & psychol. – an external stimulus that elicits a particular behavioural or chemical response
releasor – n. – 1. law – a person who surrenders a claim of legal action especially in relation to an estate or property; 2. a person who waives the possibility of a legal claim in exchange for something of value such as opportunities to participate in given events