Sentence:  New obligational authority for 1961 recommended in this budget for aircraft procurement ( excluding amounts for related research and construction ) totals $ 4753 million , which is $ 1390 <WSD>million</WSD> below that enacted for 1960 . 
Meaning of the word marked with <WSD> tags:  (in Roman numerals, M written with a macron over it) denoting a quantity consisting of 1,000,000 items or units