(idiomatic) To talk about history or the past.

plural of back passage

plural of back street

(now chiefly historical) The bacterium Mycobacterium tuberculosis, which causes tuberculosis.

The bacillus Salmonella enterica subsp. enterica, the cause of typhoid.

(idiomatic) Synonym of strive: to apply oneself completely to the point of physical exhaustion or incapacity. / Used other than figuratively or idiomatically: see break, back.

The gate at the back of a property, especially a residential property, often leading onto a lane.

(finance) Having mortgages as collateral.

Synonym of come to one's senses

plural of red-backed hawk