Mercury
Mercury is a Solar System planet; its chart position is expressed within the chosen zodiacal framework.
How it is defined
Placing a factor in a chart requires a date, an instant and a reference frame. Sign, house and aspect answer different questions: zodiac position, chart sector and angular relationship. They should not be treated as interchangeable.
How to read it
In interpretation it symbolises exchange, learning and ways of organising thought and speech.
A concrete example
Compare explaining an idea with listening to how someone understands it. The reading can explore the gap between intention and the message received.
Explore further
Read the proposal alongside the actual question and the other factors you really know. This website’s calculators show Sun, Moon and ascendant; studying other bodies here does not mean they are included in those results.