To dream that you cross a line signifies a new relationship. You can enter a new phase in life.
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Threshold If you saw a threshold, which you tried to pass, then such dream denotes to the new period of your life. Probably the risks you took will attain over and above. On the negative note, the dream could represent your tendency to take risks, but as the bad omen could be interpreted only if you fell of the threshold.
Threshold The most important thing is our attitude towards it. Stopping in front of it indicates indecision, and placing ourselves under the threshold means that we are seeking some kind of protection.